OT:Switching line voltages

[Debby and Gene Stopp]

Gosh darnit Larry, I was all set to answer this one and you beat me to it.

I agree - if you're going to control mains-voltage circuits with a small
control voltage, by all means save yourself some time and potential
headaches by using solid-state relays.

I recently bought a couple of 230V 20A units (to use for Leslie speaker
motor control, coincidentally) for $10 each at a surplus house. With one of
these, you could supply the current to light an entire house just by turning
on an LED (which is what is inside the relay, I think). The control voltage
is 3 to 32 volts (like Larry says). No current limiting resistor needed -
it's inside the relay.

These things are perfect for Leslie speakers. The old sukky
DC-bias-on-the-balanced-audio way can cause loud pops during motor speed
changes. With the SSR's, the Leslie can be cranked up till the 6550's turn
bright blue and there are NO loud popping noises when the motor speeds are
changed.

- Gene



-----Original Message-----
From: J. Larry Hendry <jlarryh at iquest.net>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Monday, December 06, 1999 7:58 PM
Subject: Re: OT:Switching line voltages


>Hey, Finally a question on synth-diy with which I know something <grin>
>
>One of the easiest ways to do this with reliability is to purchase what is
>called a solid state relay.  These have a wide range of control voltages
>and switching voltages.  A DC control voltage of 3 to 32 volts is typical.
>And, you can find them in AC load side ratings from 1 amp way up to 50 amps
>or more.  They are also available with AC switching voltages.  I used a
>couple of these to replace the TERRIBLE circuit that Hammond put in their
>860 Leslie for switching the fast and slow motors.  There is very little
>current draw on the control voltage.  Could you build this circuit yourself
>?  Sure.  But, when messing with mains, this is a safe way to keep them
>isolated from the remainder of the circuit.  Most of them come with snap
>over covers that cover the screw terminals.
>
>Larry Hendry
>
>
>----------
>> From: Plinio  Barraza <plinio at mail1.orientation.com>
>>
>> Hi I know its OT but I was hoping someone might
>> help:
>>
>> How can I switch a line voltage (110V60Hz) with
>> a small control voltage.
>>
>> At first I thought RELAY, but I don't want to
>> have to use a transformer or AC controll signal
>> (it does have to be ac right?).
>>
>> Can this be done with power transistors?
>
>
>