Re: am I a SRSG failure?

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi David,

Great!  Got it figured it out!  

If the motors really are very similar, perhaps you can simply switch rotors
between them and get your sync gap at 120VAC.  Or, the 230 volt motor may
have an easy rewire point like the 120/230 one does that you can change
even though it is not "official" on the 230 volt unit. 

Of course, converting the other motor may not be a problem and there maybe
someone out there who would take that 230 unit off your hands since 230
volts is common in pig systems...

At the least, you can now consider yourself "expert" in the sync motor
conversion area!  One learns much more when things like this don't work,
than when they do...

Just some thoughts...

Cheers,

	Terry


At 03:34 PM 8/11/00 -0400, you wrote:
>Hmmm okay how should I say this,
>I'm sorry and happy to inform all of you that it turns out that all along my
>motor *was* working the whole time -- aww, but yippee.  I just didn't
>realize it because I had what I thought were 2 identical motors, both from
>GE, same horsepower, speed etc., however, one of them is 120/230V, and the
>one I modified is only 230V.  So when I tested my motor using only (this
>made me feel intelligent, at least I undervolted this time...) 120V it
>understandably wasn't synchronous.
>    If the little metal spec. plate on the end of the motor wasn't
>sufficient, the motor's lack of torque sure was enough to tell me I wasn't
>running it right.  I tried it again yesterday night after reading all of
>your reassuring posts telling me that it simply *has* to work; I could
>easily hold the motor shaft still with my hand when I plugged it in (to
>120V).  By then my brain finally kicked into action :-)
>    But not all is a loss because regardless, I did learn a lot from your
>replies, and hey- it coulda been worse.
>
>Whew!
>Thanks for your knowlege, Dave
>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Thursday, August 10, 2000 2:20 PM
>Subject: Re: am I a SRSG failure?
>
>
>> Original poster: FutureT-at-aol-dot-com
>>
>> In a message dated 8/9/00 6:48:21 PM Pacific Daylight Time,
>tesla-at-pupman-dot-com
>> writes:
>>
>> > before I ever modified it.
>> >      What's wrong?  I made sure to make the flats the same width as the
>> "dead
>> >  poles" (which are the width of 3 poles right?)  And they are not off
>the
>> 180
>> >  degree marks either.  I just don't see what is wrong with the flats as
>far
>> > as
>> >  the examples I used of other modified motors.  Possibly I should mill
>the
>> > flats
>> >  more?
>> >
>> >  Dave
>> >
>> Dave,
>>
>> Three questions:  What is the motor horsepower, is a rotor disc
>> attached to the motor, and are you sure it's not locked now?
>> Some folks have a very hard time telling using a flourescent
>> lamp if the rotor is locked, because the pattern will be fuzzy.
>> I assume you attached at least a cardboard disc to the motor
>> with a heavy black or white line drawn across it.  It's helpful
>> to put the motor on a variac so you can gradually increase
>> the voltage and see the rotating pattern.... and see when it
>> locks.... at what voltage, etc.  If you have a heavy rotor disc
>> attached, it may be loading the motor too much to make it
>> lock up.  If you variac is the type that goes up to 140 volts,
>> the 140 volts may help to lock it up also.
>>
>> I don't use the "width of the dead poles" to modify my motors.
>> I go by proportion; If the armature is 3 3/8" diameter, the flats
>> should prpobably be about 1 1/8" wide, in other words the
>> flat width should be 1/3" the diameter of armature or so, but
>> it's not really too critical.
>>
>> I would not say that you are a SRSG failure.... optimism,
>> persistance, and learning, is the name of the game here    :)
>>
>> Cheers,
>> John Freau
>>
>>
>>
>>
>