Can I use an SSR with a motor - What about 220v? 1

[Douggg]

I'd like to know if I can use SSRs with a motor? If the motor is 220v do I use one on each leg?

Here's my application. I'm installing new pumps for my swiming pool. Filter and booster. After pricing the cost of a timer switch, (around $400) I got the idea of using SSRs.

My pumps are 220v and draw 8 amps when running. I have several SSR rated at 20a 30-280vac I was thinking of using a pair, one on each leg of the AC. (I’m in the US.) Or is there something wrong with my thinking?

Now for the timer. I have 2 empty spots on garden sprinkler system timer. Garden sprinkler solenoids are 24vac. My thinking is to use a diode (to make the AC DC), and add a cap (to smooth out the half wave).

See where I am going with this?

Here are my questions.

Can SSRs be used to control motors?
Or is there a problem with in-rush amperage?
Get too hot with motors?

Can they be used on 220v sinlge phase motors?
Do I use 1? Just one on one of the hot legs?
Or use 2? One on each of the hot legs?

Can 3-32vdc SSRs be controlled with 24vac? Do I need a diode and a cap? Or will the diode in the SSR work without the need for additional components?

Thanks for your advice.

 

[OperaHouse]

No capacitor! Don't let that get out, I've sold hundreds of thousands of those RC networks. Our garden variety that would solve every problem known to man was 0.47uF with a 220 ohm resistor.

 

[itsmoked]

[flush]
Sorry Opera... I didn't realize I'd be cutting into your bottom line!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Skogsgurra]

Now that this thread has returned to more reasonable proportions - I mean snubbers being 0.47 uF and not 47 uF or 1 pF - I cannot help joining again.

As I said 3 Jul 06 13:10 and as Keith said 3 Jul 06 16:58, the capacitors (mostly with an additional resistor) serve to suppress HF interference during switching.

The link that the OP refers to in his 3 Jul 06 16:29 post is about capacitors for power factor compensation and has absolutely nothing to do with capacitors "to prevent arcing". The whole thread is completely weird and should have been RFd from the beginning.

Also, snubbers are normally not connected across contacts but across coils.

Gunnar Englund

http://www.gke.org