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skinny · 09-19-2011, 01:08 AM

I am running a BCS controlled HERMS rig with SSRs switching the power to my heating elements and a March pump. For some reason, the pump will not start when plugged into the outlet fed through the SSR. It makes a loud humming noise and you can see the internal fan turning very slowly, but it never gets going. If you plug the pump directly into an always hot outlet, it starts and runs fine. The weird part is that if you start it on the hot outlet and then quickly plug it into the switched outlet before it has time to completely stop, it will run fine. I am starting to think that the motor is not drawing enough current through the SSR to start moving. I have tried swapping out the SSR with no luck. Has anyone ever heard of a problem like this or have any ideas as to what might be causing it?

4xtreme · 09-19-2011, 01:25 AM

I have a coulpe questions. Is the controller out put to the ssr on . Be couse solid state relayed are not like mechical one, they leak small amounts of electricity.

skinny · 09-19-2011, 01:29 AM

Yes the output to the SSR is on. The LED on the SSR lights up and you can hear the humming and the motor tries to turn. When the output is off, you don't hear or see anything.

4xtreme · 09-19-2011, 01:36 AM

Ok. Take your fluke mm and check to see that you have 120v ac from the commen to the nutral. If you have a 120 v ac check the amount of amperage the ssr is good for . I my self have not had this problem be for so keep post we will get you going .

mattd2 · 09-19-2011, 02:00 AM

Just to make sure, you are not trying to run the pump at a reduce power or anything like that using PWM? Why did you go with a SSR and not a mechanical relay?
I know these questions aren't going to help but the more info we have the more we can help

4xtreme · 09-19-2011, 02:06 AM

was thing about that my self mechanical would be a lot better . In less he has it on a level system were the pump would come on and off all the time . that could be hard on a mechanical relay.

skinny · 09-19-2011, 05:59 AM

Quote:

Originally Posted by 4xtreme

Ok. Take your fluke mm and check to see that you have 120v ac from the commen to the nutral. If you have a 120 v ac check the amount of amperage the ssr is good for . I my self have not had this problem be for so keep post we will get you going .

I will check the voltage when I get home in the morning. The SSR is a 40amp that I already had.

Quote:

Originally Posted by mattd2

Just to make sure, you are not trying to run the pump at a reduce power or anything like that using PWM? Why did you go with a SSR and not a mechanical relay?
I know these questions aren't going to help but the more info we have the more we can help

I am not trying to reduce power at all. Just turn on or off. I went with a SSR partly because I was planning on adding level switches in the future, but mainly because I already had some extras laying around.

audger · 09-19-2011, 05:45 PM

have you verified that anything else, like a lightbulb or other resistive load, would run from that SSR? the voltage wouldnt rule out a fully or partially dead SSR (although a low voltage would signal problems, a normal voltage wouldnt rule them out).

checking the current is a better indicator. a good way to do that is to plug a 100-150w incandessant bulb into the wall, note the brightness, and then try it on the SSR. if it looks less bright, its not being fed enough power. the best method would be to measure the current draw of the actual pump, but that can be difficult if you dont have the tools.

skinny · 09-19-2011, 07:27 PM

Quote:

Originally Posted by audger

have you verified that anything else, like a lightbulb or other resistive load, would run from that SSR? the voltage wouldnt rule out a fully or partially dead SSR (although a low voltage would signal problems, a normal voltage wouldnt rule them out).

checking the current is a better indicator. a good way to do that is to plug a 100-150w incandessant bulb into the wall, note the brightness, and then try it on the SSR. if it looks less bright, its not being fed enough power. the best method would be to measure the current draw of the actual pump, but that can be difficult if you dont have the tools.

It has 120v when nothing is plugged into the SSR plug both when it is off or on. With the pump plugged in and the SSR on I am showing about 75v on another outlet in parallel. With the pump running on the non-switched outlet it draws 1.45amps. With it trying to run on the SSR switched outlet it draws 3.8amps.

cruelkix · 09-19-2011, 10:05 PM

Quote:

Originally Posted by skinny

It has 120v when nothing is plugged into the SSR plug both when it is off or on. With the pump plugged in and the SSR on I am showing about 75v on another outlet in parallel. With the pump running on the non-switched outlet it draws 1.45amps. With it trying to run on the SSR switched outlet it draws 3.8amps.

A march pump should not be drawing 3.8 amps.

It sounds like your wiring is messed up somehow. You best bet for getting a solution would be posting a wiring diagram and a picture of your control panel I would think.