Hello,
MCOV is maximum continuous operating voltage - this is the voltage where
start-up current of the arrester has raised to 1 mA and the arrester is just
starting to conduct significant current.
Dick
-----Original Message-----
From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of
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To: tesla@xxxxxxxxxx
Subject: Tesla Digest, Vol 123, Issue 6
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Today's Topics:
1. Re: "Terry" filter and safety gap questions for pole
transformer (Teslalabor)
2. Re: "Terry" filter and safety gap questions for pole
transformer (Bert Hickman)
3. Re: "Terry" filter and safety gap questions for pole
transformer (Bert Hickman)
4. Re: "Terry" filter and safety gap questions for pole
transformer (Yurtle Turtle)
5. Fwd: Bleeder resistor for Maxwell cap (dennis otmaskin)
6. Fwd: Bleeder resistor for Maxwell cap (dennis otmaskin)
7. Re: Fwd: Bleeder resistor for Maxwell cap (jimlux)
8. Re: Fwd: Bleeder resistor for Maxwell cap (jhowson4)
9. RF ground cable and termination (Albert)
10. Three phase to Ballast? (jhowson4)
11. Re: Three phase to Ballast? (David Speck)
12. Re: Three phase to Ballast? (jhowson4)
----------------------------------------------------------------------
Message: 1
Date: Sat, 10 Feb 2018 16:05:54 +0100
From: Teslalabor <teslalabor@xxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] "Terry" filter and safety gap questions for pole
transformer
Message-ID: <c047eef2-ced4-bc55-f50e-1f5ffc6ba9a8@xxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8; format=flowed
I think the safest environment for the transformer is when it is used in a
DC Resonant charging system.
Am 10.02.2018 um 15:51 schrieb Phil:
> All,
>
> I have always run my pig (~10kva) without any protection in the belief
> that a Synchronous rotary significantly reduces the likelihood of HV
> transients occurring, with ARSG's and statics being the usual
> candidates. Am I correct in this assumption, or as I'm now wondering,
> totally wrong?
>
> Phil
>
> www.youtube.com/user/follytowers
>
>
> On 10/02/18 13:32, David Rieben wrote:
>> Hi Steve,
>>
>> As Bert has already pointed out, pole transformers, i.e. 'pole pigs'
>> are not totally impervious to being damaged by the HV transient
>> "nasties" that are always generated by the active resonant circuit of
>> a spark gap driven TC. That being said, pole pigs are certainly the
>> transformer of choice that is available to serious coiling hobbiests
>> that crave plenty of power and their robust design certainly renders
>> them VERY resistant to sustaining damage due to the aforementioned
>> phenomenon.
>>
>> Although you didn't mention the resistance rating of your wire wound
>> resistors, just the POWER rating (100 watts), I assume that they are
>> also rated at 100 Ohms, from the figures that you plugged into your
>> I*2 x R formula? If that's the case, then yes, your setup should be
>> fine.
>>
>> I originally ran my big coil (up to around 18 kVA with 12 to 13 ft.
>> arcs!) with ZERO protection (and NEVER had a mishap with the
>> transformer), but eventually decied that I should at least attempt
>> some form of protection. Since all of my protective horn gap attempts
>> for a pole pig output usually failed to extinguish once it "fired",
>> due to the heavy current arc that formed, I personally have been
>> using distribution arresters for this purpose. (Yup, the devices that
>> your local utility opower company use to protect their equipment from
>> line transient spikes, due to switching surges and lightning
>> strikes). I place them in parallel with the output of my pole pig
>> power supply (also a 10 kVA, 14,400-120/240 volt unit) to address
>> this issue:
>>
>>
https://www.ebay.com/itm/HUBBELL-OPTIMA-DIST-ARRESTER-2137157314-PDV100-HD/2
72071557889?rt=nc&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D4
4039%26meid%3D5a3f17733d7642709f701c4fa0ba8f8f%26pid%3D100005%26rk%3D1%26rkt
%3D1%26sd%3D272469016073%26itm%3D272071557889&_trksid=p2047675.c100005.m1851
>>
>>
>> With a little persistence, these can sometimes be found on eBay for <
>> $50. I originally started with an 18 kV rated unit, but it eventually
>> died as a short circuit. An 18 kV rated arrester is generally rated
>> for 15.8 kV MCOV (maximum circuit operating voltage - I believe) and
>> my varaic stack was able to provide up to 280 volts input, which
>> would translate to 16.8 kV out. My local power company uses 18 kV
>> arresters on their 13.2 kV primary line circuits. After this
>> incident, I upgraded to a 27 kV rated arrester and have been running
>> without a hitch ever since. I also more recently located some 21 kV
>> rated arresters and have replaced one of the 27 kV rated ones with
>> this. (I use the higher rated one right at the (Async)SG assembly and
>> the lower rated one at the transformer's output).
>>
>> I have personally had far more issues with the nasty transient
>> kickbacks on the primary LV side of my pole pig than the secondary HV
>> side. As stated before, although the HV windings of a pole pig are
>> not totally bullet proof to these kickbacks, they are much more
>> robust than the fragile NSTs or OBITs and are actually quite unlikely
>> to sustain debilitating damage from this issue. The MUCH bigger
>> problem, for me at least, has been what the transformer sends down
>> stream to the components on the LV voltage input to the transformer.
>> I use two industrial line filters that are rated to handle the
>> amperage (and a small line filter at the input of each of my two
>> cabinet cooling fans), as well as three paralleled 1 KW rated, 1 ohm,
>> ribbon style, wire wound power resistors (for 0.33 ohms total) in
>> series with my inductive ballast, AND a pair of 150 Vrms MOVs between
>> each 'hot' leg of the incoming 240 volts and the ground to combat
>> this problem!
>>
>>
https://www.ebay.com/itm/Panasonic-ERZC20EK241-150Vrms-Metal-Oxide-Varistor-
Chassis-Mount-3-pcs/160706951833?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055
119.m1438.l2649
>>
>>
>> Finally, I typically run my coil with about 75 to 80 amps draw with
>> variac set for about 200 volts input to the transformer, so that
>> translates to around 15 to 16 kVA and my transfomrmer never even
>> breaks a sweat processing this rate of power. So you definitely have
>> plenty of room for "expansion" with your power!
>>
>> Hope this helps,
>> David
>>
>> ----- Original Message ----- From: "Steve White"
>> <steve.white1@xxxxxxxxx>
>> To: "Tesla Coil List" <tesla@xxxxxxxxxx>
>> Sent: Friday, February 09, 2018 5:37 PM
>> Subject: [TCML] "Terry" filter and safety gap questions for pole
>> transformer
>>
>>
>>> My spark gap coil has been running for about 6 months with a 10 KVA
>>> pole transformer for power. I pull about 4.8 KW from the wall. The
>>> only transformer protection that I am currently using is a horn gap
>>> in parallel with the spark gap. I have had no trouble with it but
>>> lately I have become concerned with damaging the pole transformer.
>>> Because of this concern, I am in the process of building a low pass
>>> RC ("Terry") filter for additional protection. I have 2 questions
>>> regarding the resistors. I see that people are using standard
>>> wire-wound resistors. I am surprised that the 14.4 HV RMS does not
>>> flash across the windings in the resistor. Is this type of resistor
>>> indeed adequate for such high voltage? The second question concerns
>>> the power rating of the resistor. Since my worst-case RMS current
>>> from the pole transformer is no more than 0.5 amperes, the power
>>> dissipation should be no more than about 25 watts.
>>>
>>> Power = (I**2) * R = 0.5 * 0.5 * 100 = 25 watts
>>>
>>> Therefore I assume that a pair of 100 watt resistors, one on each HV
>>> lead, should be more than adequate even for a pole transformer. Is
>>> this correct?
>>>
>>> I also have a safety gap question. My safety gap is just a simple
>>> 2-terminal horn gap connected in parallel with my RSG. I see that
>>> the safety gaps used for NSTs consist of 3 terminals: 2 for the high
>>> voltage leads and a central ground terminal. For pole transformers,
>>> is there any advantage favoring the 3-terminal gap vs the 2-terminal
>>> gap?
>>>
>>> Steve
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxxxxxxxxxx
>>> https://www.pupman.com/mailman/listinfo/tesla
>>
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
------------------------------
Message: 2
Date: Sat, 10 Feb 2018 09:49:05 -0600
From: Bert Hickman <bert@xxxxxxxxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] "Terry" filter and safety gap questions for pole
transformer
Message-ID:
<6eeaaeec-f566-c061-b2e3-5b6e64901571@xxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=UTF-8; format=flowed
Hi Phil,
The type of spark gap really doesn't matter. All types of short air
spark gaps break down within nanoseconds, and in a pole-transformer TC,
typically at 20+ kV. The abrupt voltage and current transitions excite
high-amplitude, multi-MHz oscillations within the stray capacitances and
inductances in nearby HV supply wiring, AND within your unprotected
transformer's HV winding. That pole transformers usually survive this
environment is really a tribute to their robust insulation system.
It's a crap shoot. Maybe one in 100 pole transformers may eventually
fail under the stress. Older transformers, with age or heat-degraded
insulation, might be more susceptible. But it's painful if YOURS happens
to be the failing one - particularly when prevention is relatively
inexpensive and simple.
Bert
Phil wrote:
> All,
>
> I have always run my pig (~10kva) without any protection in the belief
> that a Synchronous rotary significantly reduces the likelihood of HV
> transients occurring, with ARSG's and statics being the usual
> candidates. Am I correct in this assumption, or as I'm now wondering,
> totally wrong?
>
> Phil
>
> www.youtube.com/user/follytowers
>
>
> On 10/02/18 13:32, David Rieben wrote:
>> Hi Steve,
>>
>> As Bert has already pointed out, pole transformers, i.e. 'pole pigs'
>> are not totally impervious to being damaged by the HV transient
>> "nasties" that are always generated by the active resonant circuit of
>> a spark gap driven TC. That being said, pole pigs are certainly the
>> transformer of choice that is available to serious coiling hobbiests
>> that crave plenty of power and their robust design certainly renders
>> them VERY resistant to sustaining damage due to the aforementioned
>> phenomenon.
>>
>> Although you didn't mention the resistance rating of your wire wound
>> resistors, just the POWER rating (100 watts), I assume that they are
>> also rated at 100 Ohms, from the figures that you plugged into your
>> I*2 x R formula? If that's the case, then yes, your setup should be fine.
>>
>> I originally ran my big coil (up to around 18 kVA with 12 to 13 ft.
>> arcs!) with ZERO protection (and NEVER had a mishap with the
>> transformer), but eventually decied that I should at least attempt
>> some form of protection. Since all of my protective horn gap attempts
>> for a pole pig output usually failed to extinguish once it "fired",
>> due to the heavy current arc that formed, I personally have been using
>> distribution arresters for this purpose. (Yup, the devices that your
>> local utility opower company use to protect their equipment from line
>> transient spikes, due to switching surges and lightning strikes). I
>> place them in parallel with the output of my pole pig power supply
>> (also a 10 kVA, 14,400-120/240 volt unit) to address this issue:
>>
>>
https://www.ebay.com/itm/HUBBELL-OPTIMA-DIST-ARRESTER-2137157314-PDV100-HD/2
72071557889?rt=nc&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D4
4039%26meid%3D5a3f17733d7642709f701c4fa0ba8f8f%26pid%3D100005%26rk%3D1%26rkt
%3D1%26sd%3D272469016073%26itm%3D272071557889&_trksid=p2047675.c100005.m1851
>>
>>
>> With a little persistence, these can sometimes be found on eBay for <
>> $50. I originally started with an 18 kV rated unit, but it eventually
>> died as a short circuit. An 18 kV rated arrester is generally rated
>> for 15.8 kV MCOV (maximum circuit operating voltage - I believe) and
>> my varaic stack was able to provide up to 280 volts input, which would
>> translate to 16.8 kV out. My local power company uses 18 kV arresters
>> on their 13.2 kV primary line circuits. After this incident, I
>> upgraded to a 27 kV rated arrester and have been running without a
>> hitch ever since. I also more recently located some 21 kV rated
>> arresters and have replaced one of the 27 kV rated ones with this. (I
>> use the higher rated one right at the (Async)SG assembly and the lower
>> rated one at the transformer's output).
>>
>> I have personally had far more issues with the nasty transient
>> kickbacks on the primary LV side of my pole pig than the secondary HV
>> side. As stated before, although the HV windings of a pole pig are not
>> totally bullet proof to these kickbacks, they are much more robust
>> than the fragile NSTs or OBITs and are actually quite unlikely to
>> sustain debilitating damage from this issue. The MUCH bigger problem,
>> for me at least, has been what the transformer sends down stream to
>> the components on the LV voltage input to the transformer. I use two
>> industrial line filters that are rated to handle the amperage (and a
>> small line filter at the input of each of my two cabinet cooling
>> fans), as well as three paralleled 1 KW rated, 1 ohm, ribbon style,
>> wire wound power resistors (for 0.33 ohms total) in series with my
>> inductive ballast, AND a pair of 150 Vrms MOVs between each 'hot' leg
>> of the incoming 240 volts and the ground to combat this problem!
>>
>>
https://www.ebay.com/itm/Panasonic-ERZC20EK241-150Vrms-Metal-Oxide-Varistor-
Chassis-Mount-3-pcs/160706951833?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055
119.m1438.l2649
>>
>>
>> Finally, I typically run my coil with about 75 to 80 amps draw with
>> variac set for about 200 volts input to the transformer, so that
>> translates to around 15 to 16 kVA and my transfomrmer never even
>> breaks a sweat processing this rate of power. So you definitely have
>> plenty of room for "expansion" with your power!
>>
>> Hope this helps,
>> David
>>
>> ----- Original Message ----- From: "Steve White" <steve.white1@xxxxxxxxx>
>> To: "Tesla Coil List" <tesla@xxxxxxxxxx>
>> Sent: Friday, February 09, 2018 5:37 PM
>> Subject: [TCML] "Terry" filter and safety gap questions for pole
>> transformer
>>
>>
>>> My spark gap coil has been running for about 6 months with a 10 KVA
>>> pole transformer for power. I pull about 4.8 KW from the wall. The
>>> only transformer protection that I am currently using is a horn gap
>>> in parallel with the spark gap. I have had no trouble with it but
>>> lately I have become concerned with damaging the pole transformer.
>>> Because of this concern, I am in the process of building a low pass
>>> RC ("Terry") filter for additional protection. I have 2 questions
>>> regarding the resistors. I see that people are using standard
>>> wire-wound resistors. I am surprised that the 14.4 HV RMS does not
>>> flash across the windings in the resistor. Is this type of resistor
>>> indeed adequate for such high voltage? The second question concerns
>>> the power rating of the resistor. Since my worst-case RMS current
>>> from the pole transformer is no more than 0.5 amperes, the power
>>> dissipation should be no more than about 25 watts.
>>>
>>> Power = (I**2) * R = 0.5 * 0.5 * 100 = 25 watts
>>>
>>> Therefore I assume that a pair of 100 watt resistors, one on each HV
>>> lead, should be more than adequate even for a pole transformer. Is
>>> this correct?
>>>
>>> I also have a safety gap question. My safety gap is just a simple
>>> 2-terminal horn gap connected in parallel with my RSG. I see that the
>>> safety gaps used for NSTs consist of 3 terminals: 2 for the high
>>> voltage leads and a central ground terminal. For pole transformers,
>>> is there any advantage favoring the 3-terminal gap vs the 2-terminal
>>> gap?
>>>
>>> Steve
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxxxxxxxxxx
>>> https://www.pupman.com/mailman/listinfo/tesla
>>
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
>
>
------------------------------
Message: 3
Date: Sat, 10 Feb 2018 10:21:11 -0600
From: Bert Hickman <bert@xxxxxxxxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] "Terry" filter and safety gap questions for pole
transformer
Message-ID:
<ce03aad2-f8a7-4422-afa5-744e36799c18@xxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=UTF-8; format=flowed
Hi Steve,
A three-terminal gap is only necessary if you're using a two-eared pole
transformer with both HV outputs floating versus ground. This provides a
safe path to ground in case of a primary strike.
Many coilers ground one end of the pole transformer's HV winding, and
also connect this to the inner-most primary turn of the primary, and RF
ground. In this case, a two-terminal gap is fine.
Bert
--
Bert Hickman
Stoneridge Engineering LLC
http://www.capturedlightning.com
+1 630-964-2699
***********************************************************************
World's source for "Captured Lightning" Lichtenberg Figure sculptures,
magnetically "shrunken" coins, and scarce/out of print technical books
***********************************************************************
Steve White wrote:
<snip>
> I also have a safety gap question. My safety gap is just a simple
2-terminal horn gap connected in parallel with my RSG. I see that the safety
gaps used for NSTs consist of 3 terminals: 2 for the high voltage leads and
a central ground terminal. For pole transformers, is there any advantage
favoring the 3-terminal gap vs the 2-terminal gap?
>
> Steve
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
>
>
------------------------------
Message: 4
Date: Sat, 10 Feb 2018 19:46:00 +0000 (UTC)
From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>, David Rieben
<drieben@xxxxxxx>
Subject: Re: [TCML] "Terry" filter and safety gap questions for pole
transformer
Message-ID: <2062640396.5423363.1518291960904@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset=UTF-8
I got my 7.2/14.4 kV 25 kVA pig with an 18 kV arrestor. Given that my pig
was located in the Styx - I literally cut down the pole - it was likely 7200
volts. Mine worked up to 280 volt input, but the arrestor would occasionally
kick in, resulting in frequent temporary dropouts in pig output, and erratic
coil behavior. Mine hasn't shorted yet, but eventually would have, as they
are only good for so many events, as I understand them. I'm currently
running with nothing, but need to get a higher rated arrestor.
I have a 2 horned pig, but ground one end. So electrically, one horn gets
shorted to the other horn, the way I had my arrestor.
If I understand you, you are using a second arrester across your SRSG, as a
safety gap?
On Saturday, February 10, 2018, 8:56:55 AM EST, David Rieben
<drieben@xxxxxxx> wrote:
Hi Steve,
As Bert has already pointed out, pole transformers, i.e. 'pole pigs' are not
totally impervious to being damaged by the HV transient "nasties" that are
always generated by the active resonant circuit of a spark gap driven TC.
That being said, pole pigs are certainly the transformer of choice that is
available to serious coiling hobbiests that crave plenty of power and their
robust design certainly renders them VERY resistant to sustaining damage due
to the aforementioned phenomenon.
Although you didn't mention the resistance rating of your wire wound
resistors, just the POWER rating (100 watts), I assume that they are also
rated at 100 Ohms, from the figures that you plugged into your I*2 x R
formula? If that's the case, then yes, your setup should be fine.
I originally ran my big coil (up to around 18 kVA with 12 to 13 ft. arcs!)
with ZERO protection (and NEVER had a mishap with the transformer), but
eventually decied that I should at least attempt some form of protection.
Since all of my protective horn gap attempts for a pole pig output usually
failed to extinguish once it "fired", due to the heavy current arc that
formed, I personally have been using distribution arresters for this
purpose. (Yup, the devices that your local utility opower company use to
protect their equipment from line transient spikes, due to switching surges
and lightning strikes). I place them in parallel with the output of my pole
pig power supply (also a 10 kVA, 14,400-120/240 volt unit) to address this
issue:
https://www.ebay.com/itm/HUBBELL-OPTIMA-DIST-ARRESTER-2137157314-PDV100-HD/2
72071557889?rt=nc&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D4
4039%26meid%3D5a3f17733d7642709f701c4fa0ba8f8f%26pid%3D100005%26rk%3D1%26rkt
%3D1%26sd%3D272469016073%26itm%3D272071557889&_trksid=p2047675.c100005.m1851
With a little persistence, these can sometimes be found on eBay for < $50. I
originally started with an 18 kV rated unit, but it eventually died as a
short circuit. An 18 kV rated arrester is generally rated for 15.8 kV MCOV
(maximum circuit operating voltage - I believe) and my varaic stack was able
to provide up to 280 volts input, which would translate to 16.8 kV out. My
local power company uses 18 kV arresters on their 13.2 kV primary line
circuits. After this incident, I upgraded to a 27 kV rated arrester and have
been running without a hitch ever since. I also more recently located some
21 kV rated arresters and have replaced one of the 27 kV rated ones with
this. (I use the higher rated one right at the (Async)SG assembly and the
lower rated one at the transformer's output).
I have personally had far more issues with the nasty transient kickbacks on
the primary LV side of my pole pig than the secondary HV side. As stated
before, although the HV windings of a pole pig are not totally bullet proof
to these kickbacks, they are much more robust than the fragile NSTs or OBITs
and are actually quite unlikely to sustain debilitating damage from this
issue. The MUCH bigger problem, for me at least, has been what the
transformer sends down stream to the components on the LV voltage input to
the transformer. I use two industrial line filters that are rated to handle
the amperage (and a small line filter at the input of each of my two cabinet
cooling fans), as well as three paralleled 1 KW rated, 1 ohm, ribbon style,
wire wound power resistors (for 0.33 ohms total) in series with my inductive
ballast, AND a pair of 150 Vrms MOVs between each 'hot' leg of the incoming
240 volts and the ground to combat this problem!
https://www.ebay.com/itm/Panasonic-ERZC20EK241-150Vrms-Metal-Oxide-Varistor-
Chassis-Mount-3-pcs/160706951833?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055
119.m1438.l2649
Finally, I typically run my coil with about 75 to 80 amps draw with variac
set for about 200 volts input to the transformer, so that translates to
around 15 to 16 kVA and my transfomrmer never even breaks a sweat
processing this rate of power. So you definitely have plenty of room for
"expansion" with your power!
Hope this helps,
David
----- Original Message -----
From: "Steve White" <steve.white1@xxxxxxxxx>
To: "Tesla Coil List" <tesla@xxxxxxxxxx>
Sent: Friday, February 09, 2018 5:37 PM
Subject: [TCML] "Terry" filter and safety gap questions for pole transformer
> My spark gap coil has been running for about 6 months with a 10 KVA pole
> transformer for power. I pull about 4.8 KW from the wall. The only
> transformer protection that I am currently using is a horn gap in parallel
> with the spark gap. I have had no trouble with it but lately I have become
> concerned with damaging the pole transformer. Because of this concern, I
> am in the process of building a low pass RC ("Terry") filter for
> additional protection. I have 2 questions regarding the resistors. I see
> that people are using standard wire-wound resistors. I am surprised that
> the 14.4 HV RMS does not flash across the windings in the resistor. Is
> this type of resistor indeed adequate for such high voltage? The second
> question concerns the power rating of the resistor. Since my worst-case
> RMS current from the pole transformer is no more than 0.5 amperes, the
> power dissipation should be no more than about 25 watts.
>
> Power = (I**2) * R = 0.5 * 0.5 * 100 = 25 watts
>
> Therefore I assume that a pair of 100 watt resistors, one on each HV lead,
> should be more than adequate even for a pole transformer. Is this correct?
>
> I also have a safety gap question. My safety gap is just a simple
> 2-terminal horn gap connected in parallel with my RSG. I see that the
> safety gaps used for NSTs consist of 3 terminals: 2 for the high voltage
> leads and a central ground terminal. For pole transformers, is there any
> advantage favoring the 3-terminal gap vs the 2-terminal gap?
>
> Steve
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxxxxxx
https://www.pupman.com/mailman/listinfo/tesla
------------------------------
Message: 5
Date: Sun, 11 Feb 2018 16:15:56 -0500
From: dennis otmaskin <dotmaskin@xxxxxxxxx>
To: tesla@xxxxxxxxxxxxxxxxxx
Subject: [TCML] Fwd: Bleeder resistor for Maxwell cap
Message-ID:
<CALChhDA2Q93hCowwKvPd35+BTJix99afi5g4z1K6ErB0ZZmG7A@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
----Subject: Re: [TCML] Bleeder resistor for Maxwell cap
Thanks guys for your helpful responses. To answer Gary's question, my
Maxwell cap is .03uF (not .003uF which was a typo in my earlier email).
Here are the key points I take away from your suggestions:
- To keep it simple, I'll attempt to duplicate the values of Gary's
bleeder resistor configuration: 78Meg, 1/4W. Since this works for his
.04uF cap it should also work for my .03uF cap...right?
- I'll use 2 or more separate sets of bleeders across the cap to act as a
safety back up.
- I will also use use a bang stick each time for added safety measure.
I do have a question: in lieu of putting together a string of 39 resistors
as Gary has, I'd like to see if I can safely get the same value in a single
High Voltage resistor. I've tried checking the product specs on DigiKey's
& Mouser's websites, but honestly it got a little confusing for me with all
the additional specifications to choose from. Could one of you suggest a
specific type of resistor that would do the job? If possible a part number
would also really be helpful.
Thanks, Dennis MA
On Sat, Feb 10, 2018 at 3:01 PM, dennis otmaskin <dotmaskin@xxxxxxxxx>
wrote:
>
>
>
> Begin forwarded message:
>
> *From:* Gary Lau <glau1024@xxxxxxxxx>
> *Date:* February 7, 2018 at 10:30:18 PM EST
> *To:* Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> *Subject:* *Re: [TCML] Bleeder resistor for Maxwell cap*
> *Reply-To:* Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>
> Hi Dennis,
>
> The specs for a bleeder resistor are anything but critical. Was your cap
> .003 uF or .03uF? I use a .04uF cap. I constructed a bleeder out
> of thirty nine 2.0Meg 1/4W resistors (78Meg total). I calculated that
with
> my .04uF cap, the time constant (R*C) is 3.2 sec. Five times the time
> constant is generally regarded as how long it takes to completely
discharge
> the cap. My bleeder is pictured here, 5th photo from the top:
> http://www.laushaus.com/tesla/sync_gap.htm
> 1/4W resistors are normally not recommended for HV, but having so many in
> series keeps the voltage per resistor to acceptable limits. The important
> thing is to make sure that it's soundly constructed and wired to the cap.
> 78 Meg is higher than most multimeters can read so you need to be creative
> in verifying that sub-sections of the series chain are intact, thereby
> implying that the entire chain is wired intact.
>
> <http://www.avg.com/email-signature?utm_medium=email&utm_
> source=link&utm_campaign=sig-email&utm_content=webmail>
> Virus-free.
> www.avg.com
> <http://www.avg.com/email-signature?utm_medium=email&utm_
> source=link&utm_campaign=sig-email&utm_content=webmail>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Wed, Feb 7, 2018 at 1:40 PM, dennis otmaskin <dotmaskin@xxxxxxxxx>
> wrote:
>
> I would appreciate some guidance on the proper bleeder resistor for a 35kV
>
> .003uF Maxwell pulse capacitor (#367667) or where I can go to find this
>
> info. Thank you!
>
>
> Dennis, Hopkinton MA
>
> _______________________________________________
>
> Tesla mailing list
>
> Tesla@xxxxxxxxxxxxxxxxxx
>
> https://www.pupman.com/mailman/listinfo/tesla
>
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
------------------------------
Message: 6
Date: Sun, 11 Feb 2018 16:26:20 -0500
From: dennis otmaskin <dotmaskin@xxxxxxxxx>
To: tesla@xxxxxxxxxxxxxxxxxx
Subject: [TCML] Fwd: Bleeder resistor for Maxwell cap
Message-ID:
<CALChhDAEYhW0d0FmdBTDi8s2+qH1P2h+nsShu1QFs34_0ftoxQ@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
Subject: Bleeder resistor for a Maxwell cap
Thanks guys for your helpful responses. To answer Gary's question, my
Maxwell cap is .03uF (not .003uF which was a typo in my earlier email).
Here are the key points I take away from your suggestions:
- To keep it simple, I'll attempt to duplicate the values of Gary's
bleeder resistor configuration: 78Meg, 1/4W. Since this works for his
.04uF cap it should also work for my .03uF cap...right?
- I'll use 2 or more separate sets of bleeders across the cap to act as a
safety back up.
- I will also use use a bang stick each time for added safety measure.
I do have a question: in lieu of putting together a string of 39 resistors
as Gary has, I'd like to see if I can safely get the same value in a single
High Voltage resistor. I've tried checking the product specs on DigiKey's
& Mouser's websites, but honestly it got a little confusing for me with all
the additional specifications to choose from. Could one of you suggest a
specific type of resistor that would do the job? If possible a part number
would also really be helpful.
Thanks, Dennis MA
On Sat, Feb 10, 2018 at 3:01 PM, dennis otmaskin <dotmaskin@xxxxxxxxx>
wrote:
>
>
>
> Begin forwarded message:
>
> *From:* Gary Lau <glau1024@xxxxxxxxx>
> *Date:* February 7, 2018 at 10:30:18 PM EST
> *To:* Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> *Subject:* *Re: [TCML] Bleeder resistor for Maxwell cap*
> *Reply-To:* Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>
> Hi Dennis,
>
> The specs for a bleeder resistor are anything but critical. Was your cap
> .003 uF or .03uF? I use a .04uF cap. I constructed a bleeder out
> of thirty nine 2.0Meg 1/4W resistors (78Meg total). I calculated that
with
> my .04uF cap, the time constant (R*C) is 3.2 sec. Five times the time
> constant is generally regarded as how long it takes to completely
discharge
> the cap. My bleeder is pictured here, 5th photo from the top:
> http://www.laushaus.com/tesla/sync_gap.htm
> 1/4W resistors are normally not recommended for HV, but having so many in
> series keeps the voltage per resistor to acceptable limits. The important
> thing is to make sure that it's soundly constructed and wired to the cap.
> 78 Meg is higher than most multimeters can read so you need to be creative
> in verifying that sub-sections of the series chain are intact, thereby
> implying that the entire chain is wired intact.
>
> <http://www.avg.com/email-signature?utm_medium=email&utm_
> source=link&utm_campaign=sig-email&utm_content=webmail>
> Virus-free.
> www.avg.com
> <http://www.avg.com/email-signature?utm_medium=email&utm_
> source=link&utm_campaign=sig-email&utm_content=webmail>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Wed, Feb 7, 2018 at 1:40 PM, dennis otmaskin <dotmaskin@xxxxxxxxx>
> wrote:
>
> I would appreciate some guidance on the proper bleeder resistor for a 35kV
>
> .003uF Maxwell pulse capacitor (#367667) or where I can go to find this
>
> info. Thank you!
>
>
> Dennis, Hopkinton MA
>
> _______________________________________________
>
> Tesla mailing list
>
> Tesla@xxxxxxxxxxxxxxxxxx
>
> https://www.pupman.com/mailman/listinfo/tesla
>
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
------------------------------
Message: 7
Date: Sun, 11 Feb 2018 13:46:55 -0800
From: jimlux <jimlux@xxxxxxxxxxxxx>
To: tesla@xxxxxxxxxxxxxxxxxx
Subject: Re: [TCML] Fwd: Bleeder resistor for Maxwell cap
Message-ID: <366d2bba-140c-bc66-b9e9-b5c7c3483718@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8; format=flowed
On 2/11/18 1:26 PM, dennis otmaskin wrote:
> Subject: Bleeder resistor for a Maxwell cap
>
> I do have a question: in lieu of putting together a string of 39
resistors
> as Gary has, I'd like to see if I can safely get the same value in a
single
> High Voltage resistor.
That's tough - real HV resistors are really expensive. As a general
rule, a 2W resistor has a max voltage of 500-1000V, limited mostly by
the creepage distance over the case, with a healthy margin.
Free air breakdown is 70kV/inch, 30kV/cm. But that's in a uniform
field. Between needle points, it's less than 1/3 of that. And over a
surface, it's less than that.
So a 1cm long resistor is rated at 1kV (or maybe 2kV, if it's really clean).
There's also a power dissipation issue - 1kV with 1 Meg is 1 Watt of
dissipation, and that's hot. 1kV for 10 Meg is 0.1 Watt which is more
reasonable.
For the usual sort of "several hundred watt" power supply (i.e. a NST)
you don't want the resistor string dissipating 10s of watts.
------------------------------
Message: 8
Date: Sun, 11 Feb 2018 17:07:27 -0500
From: jhowson4 <jhowson4@xxxxxxxxxxx>
To: TCML tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Fwd: Bleeder resistor for Maxwell cap
Message-ID: <6i9s3i70lniqeas3dq7hjuot.1518386847537@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8
Dennis,?I may have a suitable resistor in my stash if you can't find one.
I just short my cap to ground through a grounded 100ohm 100w resistor on the
end of a insulating stick when im done for the day.?Putting a gator clip
across it for storage.?Been working for me for years.?
Contact me off list of you want me to look for a resistor for you.?
-Jay
------ Original message------From: dennis otmaskin Date: Sun, Feb 11, 2018
4:37 PMTo: tesla@xxxxxxxxxx;Cc: Subject:[TCML] Fwd: Bleeder resistor for
Maxwell cap
Subject: Bleeder resistor for a Maxwell capThanks guys for your helpful
responses. To answer Gary's question, myMaxwell cap is .03uF (not .003uF
which was a typo in my earlier email).Here are the key points I take away
from your suggestions: - To keep it simple, I'll attempt to duplicate the
values of Gary'sbleeder resistor configuration: 78Meg, 1/4W. Since this
works for his.04uF cap it should also work for my .03uF cap...right? - I'll
use 2 or more separate sets of bleeders across the cap to act as asafety
back up. - I will also use use a bang stick each time for added safety
measure.I do have a question: in lieu of putting together a string of 39
resistorsas Gary has, I'd like to see if I can safely get the same value in
a singleHigh Voltage resistor. I've tried checking the product specs on
DigiKey's& Mouser's websites, but honestly it got a little confusing for me
with allthe additional specifications to choose from. Could one of you
suggest aspecific type of resi
stor that would do the job? If possible a part numberwould also really be
helpful.Thanks, Dennis MAOn Sat, Feb 10, 2018 at 3:01 PM, dennis otmaskin
wrote:>>>> Begin forwarded message:>> *From:* Gary Lau > *Date:* February 7,
2018 at 10:30:18 PM EST> *To:* Tesla Coil Mailing List > *Subject:* *Re:
[TCML] Bleeder resistor for Maxwell cap*> *Reply-To:* Tesla Coil Mailing
List >> Hi Dennis,>> The specs for a bleeder resistor are anything but
critical. Was your cap> .003 uF or .03uF? I use a .04uF cap. I
constructed a bleeder out> of thirty nine 2.0Meg 1/4W resistors (78Meg
total). I calculated that with> my .04uF cap, the time constant (R*C) is
3.2 sec. Five times the time> constant is generally regarded as how long it
takes to completely discharge> the cap. My bleeder is pictured here, 5th
photo from the top:> http://www.laushaus.com/tesla/sync_gap.htm> 1/4W
resistors are normally not recommended for HV, but having so many in> series
keeps the voltage per resistor to acc
eptable limits. The important> thing is to make sure that it's soundly
constructed and wired to the cap.> 78 Meg is higher than most multimeters
can read so you need to be creative> in verifying that sub-sections of the
series chain are intact, thereby> implying that the entire chain is wired
intact.>> source=link&utm_campaign=sig-email&utm_content=webmail>>
Virus-free.> www.avg.com>
source=link&utm_campaign=sig-email&utm_content=webmail>>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>>> On Wed, Feb 7, 2018 at 1:40 PM,
dennis otmaskin > wrote:>> I would appreciate some guidance on the proper
bleeder resistor for a 35kV>> .003uF Maxwell pulse capacitor (#367667) or
where I can go to find this>> info. Thank you!>>> Dennis, Hopkinton MA>>
_______________________________________________>> Tesla mailing list>>
Tesla@xxxxxxxxxxxxxxxxxx>> https://www.pupman.com/mailman/listinfo/tesla>>>
_______________________________________________> Tesla mailing list>
Tesla@xxxxxxxxxxxxxxxxxx> http
s://www.pupman.com/mailman/listinfo/tesla>__________________________________
_____________Tesla mailing
listTesla@tedward.pupman.comhttps://www.pupman.com/mailman/listinfo/tesla
------------------------------
Message: 9
Date: Mon, 12 Feb 2018 17:10:19 +0000
From: Albert <Animation@xxxxxxxxxxxxxx>
To: tesla@xxxxxxxxxxxxxxxxxx
Subject: [TCML] RF ground cable and termination
Message-ID: <11a969ce-6b9a-0b14-4fe0-6ba89acf84a3@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8; format=flowed
Making good progress with my first coil. (15kv.30m/a).
I am using car jump lead cables for the spark gap to primary
connections? (high amps),
but wonder if this type of cable would be OK for the RF ground lead to
the ground rods?
Also, could I terminate the cable with the large jump lead alligator
clips at each end ?
Thanks.
------------------------------
Message: 10
Date: Mon, 12 Feb 2018 18:33:19 -0500
From: jhowson4 <jhowson4@xxxxxxxxxxx>
To: TCML tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: [TCML] Three phase to Ballast?
Message-ID: <hm4arr19r3can6pha49hs5mh.1518478399383@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8
So,?I have this huge 3 phase transformer that was slated to step down 480 to
36V at 600 or so amps.?
My lack of 3 phase power has led me to wonder if I could use the transformer
as a single phase input output via keeping/using only one set of the
windings.?
Has anyone used a 3 phase transformer as a single phase unit via isolating
the unused coils and simply running just the middle leg?
Cheers,?Jay
------------------------------
Message: 11
Date: Mon, 12 Feb 2018 20:40:42 -0500
From: David Speck <Dave@xxxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Three phase to Ballast?
Message-ID: <9d1ede92-653b-b404-a8a8-8d8c20be4ea9@xxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8; format=flowed
Jay,
Aside from the three phase issue, I assume that you would be planning to
feed 120 or 240 VAC into the 36 volt windings in an attempt to get a
higher voltage (~2,300 VAC) out of the original 440 VAC terminals.
I would not expect the transformer to last very long in this mode of
operation, because the windings would not be insulated to handle such a
high voltage.? Furthermore, 2,300 volts is not a particularly high
voltage to run a TC with.? You can get nearly the same voltage out of an
ordinary microwave oven transformer that was designed to handle such a
voltage comfortably for extended periods.
Two such MOTs connected together in series at their usually grounded
cores would give you ~4,000 volts, but even that is rather low for TC
use, unless you are going for a DC resonant charging system.
Dave
On 2/12/2018 6:33 PM, jhowson4 wrote:
> So,?I have this huge 3 phase transformer that was slated to step down 480
to 36V at 600 or so amps.
> My lack of 3 phase power has led me to wonder if I could use the
transformer as a single phase input output via keeping/using only one set of
the windings.
> Has anyone used a 3 phase transformer as a single phase unit via isolating
the unused coils and simply running just the middle leg?
> Cheers,?Jay
------------------------------
Message: 12
Date: Mon, 12 Feb 2018 21:37:02 -0500
From: jhowson4 <jhowson4@xxxxxxxxxxx>
To: TCML tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Three phase to Ballast?
Message-ID: <k8ih37n4n4cqih2b1boqp81a.1518488389856@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8
Thanks Dave.?
Quite the opposite actually,?I was hoping to get 18ish or so volts at the
higher current out of it.? The windings are beautiful. Nice space wound 3
strands of hefty square magnet wire on the LV side. Can handle a bunch of
current indefinitely.?Or just use the inductance to ballast my pig. The core
area is about right. Havnt bothered to throw an LCR on it yet.Anyway.?
My uncertainty stems from the fact that the 3 phase cores have equal iron on
all 3 legs, Such that if I only energized 1 coil the magnetic loops cross
sectional area doubles and then halves again.?Not sure if this would cause a
negative effect making it an undesirable situation for a single coil single
phase use.?
I could always just cut out the middle leg... And use the two outer legs.?
Someone on Facebook suggested putting all the secondaries and primaries in
series with proper fields orientations. Maybe that works for lower power
overall.?
Regardless, Figured I'd ask the stupid questions before rigging up a test.
The garage is coldish this time of year after all.?
Cheers,?Jay
Sent from my Verizon 4G LTE Smartphone
------ Original message------From: David Speck Date: Mon, Feb 12, 2018 8:52
PMTo: Tesla Coil Mailing List;Cc: Subject:Re: [TCML] Three phase to Ballast?
Jay,Aside from the three phase issue, I assume that you would be planning to
feed 120 or 240 VAC into the 36 volt windings in an attempt to get a higher
voltage (~2,300 VAC) out of the original 440 VAC terminals.I would not
expect the transformer to last very long in this mode of operation, because
the windings would not be insulated to handle such a high voltage.?
Furthermore, 2,300 volts is not a particularly high voltage to run a TC
with.? You can get nearly the same voltage out of an ordinary microwave oven
transformer that was designed to handle such a voltage comfortably for
extended periods.Two such MOTs connected together in series at their usually
grounded cores would give you ~4,000 volts, but even that is rather low for
TC use, unless you are going for a DC resonant charging system.DaveOn
2/12/2018 6:33 PM, jhowson4 wrote:> So,?I have this huge 3 phase transformer
that was slated to step down 480 to 36V at 600 or so amps.> My lack of 3
phase power has led me to won
der if I could use the transformer as a single phase input output via
keeping/using only one set of the windings.> Has anyone used a 3 phase
transformer as a single phase unit via isolating the unused coils and simply
running just the middle leg?>
Cheers,?Jay_______________________________________________Tesla mailing
listTesla@tedward.pupman.comhttps://www.pupman.com/mailman/listinfo/tesla
------------------------------
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