Re: Soft transformer turn on without a variac

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "BunnyKiller by way of Terry Fritz <teslalist-at-qwest-dot-net>" <bunikllr-at-bellsouth-dot-net>

Tesla list wrote:

>Original poster: "Peter Terren by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <pterren-at-iinet-dot-net.au>
>
>Hi all.
>For my 5 kW museum coil, 
><http://members.iinet-dot-net.au/~pterren/Scitech.htm>http://members.iinet-dot-net.au/~pterren/Scitech.htm 
>,   I need to have a single switch for turn on preferably without a variac 
>to keep things simple for the staff.  The present system has solid state 
>relays but is complicated and unreliable. I need to turn on the motor 
>first then a couple of seconds later soft turn on the power to the 
>transformer. Even switching  on power to a normal variac gives a spike 
>that will trip my lower current breakers. The whole system will have to be 
>electrically quiet.  Does anyone have experience with inrush limiters or 
>have other suggestions?
>
>Cheers
>Peter (Tesla Downunder)


Hi  Peter...

I had a simular problem with my coil setup in a Haunted House 
situation.  To solve the problem I used a double pole double throw relay 
and a solid state timer rated for 120 V .  When switch was turned on the it 
started the timer engaging the relay which went to an inductor rated to 
deliver 5 A at 120V. After 3 seconds the timer kicked out and the relay 
switched back to deliver full voltage/amperage.   There is a slight problem 
with the design...  there is a momentary kick-off/kick-on when the timer 
turns off. ( hmmm  maybe 2 timers and 2 single pole relays would be better 
) But it was a simple design and it kept the circuit breaker from popping 
at initial turn on.

Scot D