Re: Soft transformer turn on without a variac

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

Original poster: "June Heidlebaugh by way of Terry Fritz <teslalist-at-qwest-dot-net>" <rheidlebaugh-at-desertgate-dot-com>

I use motor start solenoids which have built in surge resistors to suppress
the motor start surge current.
Robert  H
----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, July 24, 2003 8:13 AM
Subject: Re: Soft transformer turn on without a variac


 > 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
 >
 >
 >
 >
 >
 >