The project I am working on will need a relay for a 1/3 to 1/2 hp 240V
pump motor.

Have been trying to do my homework concerning possible solid state
relays to use.

So far the Teledyne S24A25 (zero crossing turn on) and the Crydom
A2425-10 (random turn on) seem quite similar except for the difference
in turn on.

Am wondering how much difference this actually makes?

Welcome any suggestions for these or other suitable solid state relays.

Thanks

Ken

In article . com, wrote:
The project I am working on will need a relay for a 1/3 to 1/2 hp 240V
pump motor.

Have been trying to do my homework concerning possible solid state
relays to use.

So far the Teledyne S24A25 (zero crossing turn on) and the Crydom
A2425-10 (random turn on) seem quite similar except for the difference
in turn on.

Am wondering how much difference this actually makes?

Welcome any suggestions for these or other suitable solid state relays.

Thanks

Ken


I was trying too use some zero crosing models for controlling a solenoid.
It became unstable at times with the inductance, and randomly pulsed
when it was not supposed to. I would recommend the standard type.

greg

On 26 Aug 2005 11:49:39 -0700, wrote:

The project I am working on will need a relay for a 1/3 to 1/2 hp 240V
pump motor.

Have been trying to do my homework concerning possible solid state
relays to use.

So far the Teledyne S24A25 (zero crossing turn on) and the Crydom
A2425-10 (random turn on) seem quite similar except for the difference
in turn on.

Am wondering how much difference this actually makes?

Welcome any suggestions for these or other suitable solid state relays.

Thanks

Ken

The principal difference is the amount of RF noise that is generated.

"Michael Gray" wrote in message
...
On 26 Aug 2005 11:49:39 -0700, wrote:

The project I am working on will need a relay for a 1/3 to 1/2 hp 240V
pump motor.

Have been trying to do my homework concerning possible solid state
relays to use.

So far the Teledyne S24A25 (zero crossing turn on) and the Crydom
A2425-10 (random turn on) seem quite similar except for the difference
in turn on.

Am wondering how much difference this actually makes?

Welcome any suggestions for these or other suitable solid state relays.

Thanks

Ken

The principal difference is the amount of RF noise that is generated.

And for an inductive load like a motor it's a particularly good idea to use
one with zero crossing.

Use the Zero Crossover one...I have been using them
on 1/2hp motors for 8 years with no failure
and they are outside where the temps are +30c
in the summer to -20c in the winter.

kip

"James Sweet" wrote in message
news:E8eQe.15165$Bc2.9331@trnddc06...

"Michael Gray" wrote in message
...
On 26 Aug 2005 11:49:39 -0700, wrote:

The project I am working on will need a relay for a 1/3 to 1/2 hp 240V
pump motor.

Have been trying to do my homework concerning possible solid state
relays to use.

So far the Teledyne S24A25 (zero crossing turn on) and the Crydom
A2425-10 (random turn on) seem quite similar except for the difference
in turn on.

Am wondering how much difference this actually makes?

Welcome any suggestions for these or other suitable solid state relays.

Thanks

Ken

The principal difference is the amount of RF noise that is generated.

And for an inductive load like a motor it's a particularly good idea to
use
one with zero crossing.

On 26 Aug 2005 11:49:39 -0700, put finger to
keyboard and composed:

The project I am working on will need a relay for a 1/3 to 1/2 hp 240V
pump motor.

Have been trying to do my homework concerning possible solid state
relays to use.

So far the Teledyne S24A25 (zero crossing turn on) and the Crydom
A2425-10 (random turn on) seem quite similar except for the difference
in turn on.

Am wondering how much difference this actually makes?

I'd concur with those who recommend the zero crossing types. For an
inductive load ...

V = L dI/dt + IR

.... so if V=0 at t=0, then I=0 and dI/dt = 0.

This ensures the softest start.

A capacitive load (eg main filter caps in PSUs) will also benefit from
zero-voltage startup as I = C dV/dt.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.