March Pump and SSR Troubles

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

skinny

Active Member
Joined
Jun 28, 2009
Messages
40
Reaction score
0
Location
Texas
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?
 
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.
 
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.
 
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 .
 
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 ;)
 
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.
 
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.

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.
 
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.
 
audger said:
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.
 
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.
 
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.

I agree it should not be drawing that much current. Here is a quick and ugly wiring diagram of this section of my rig. The ground is connected just not shown.
Diagram.JPG
When the pump is plugged into the top plug which is always hot, it runs fine and draws the 1.45a. When I plug it into the bottom outlet with the ssr switching the hot leg, it draws the 3.8a and doesn't turn.
 
I agree it should not be drawing that much current. Here is a quick and ugly wiring diagram of this section of my rig. The ground is connected just not shown.
View attachment 33958
When the pump is plugged into the top plug which is always hot, it runs fine and draws the 1.45a. When I plug it into the bottom outlet with the ssr switching the hot leg, it draws the 3.8a and doesn't turn.

I don't trust the plug I guess. Try taking them out of parallel and putting the SSR inline with the top plug that has worked before, don't connect anything to the bottom plug.
 
cruelkix said:
I don't trust the plug I guess. Try taking them out of parallel and putting the SSR inline with the top plug that has worked before, don't connect anything to the bottom plug.

Same result on top plug when controlled by ssr. I am thinking it is an issue with the lot of ssrs I have. I think I am going to order a relay board and try that. For 8 bucks, and I don't see what it would hurt.
 
a SSR will show 120v across the two control terminals even when its supposed to be off. this is normal. what is not normal is the voltage dropping to 75v when the SSR switches on. it sounds like your SSR is faulty and is partially blocking the voltage.

the high amperage reading you have is a combo of the low-voltage problem (when you halve the voltage, the amperage requirement doubles; P=IxR; so its trying to make up for the lack of voltage by essentially requesting more amperage) and the fact that the pump is not spinning.
during the space of time between when power is first supplied, and when the pump reaches operating speed, the pump (or any motor) will pull much more than its normal operating amperage. since its never getting up to operating speed, its stuck in this startup mode pulling extra amperage and burning up the brushes and contacts on the motor.

undervolting an a/c motor in this way is very bad for it, and you should stop using the pump on that relay immediately before you do any (more) damage to it, and untill you find and fix the problem.

are your SSRs rated for switching 120v AC? you sure they arent DC? the components that control the main voltage (mosfets) are arranged differently for AC than for DC; because A/C alternates, A/C SSRs use two mosfets tied to the same source with different drains (as opposed to DC SSRs which use only one mosfet, or a more parrallel configuration). so it would make sense trying to pass 120v AC thru a DC SSR that you would get around half the voltage, as it would be blocking most of the current in one direction but not the other, effectively converting it into DC.
 
...
are your SSRs rated for switching 120v AC? you sure they arent DC? the components that control the main voltage (mosfets) are arranged differently for AC than for DC; because A/C alternates, A/C SSRs use two mosfets tied to the same source with different drains (as opposed to DC SSRs which use only one mosfet, or a more parrallel configuration). so it would make sense trying to pass 120v AC thru a DC SSR that you would get around half the voltage, as it would be blocking most of the current in one direction but not the other, effectively converting it into DC.

Good call on that one. That is a strong possibility.

To the OP... Do you have a link to your SSR source?
 
I accidentally bought output DC ssrs and they worked absolutely fine reading 238V as they should have on my system. Until one day the SSR toasted itself and Walker noticed I bought the wrong type. I put another DC output one in my control box and have been using it with no issues, but plan to replace it with the AC output one (bought 2 already), when the DC SSR in place frys.

I posted this mostly to illustrate that teh DC output SSR didn't half my 240 intended AC output. Also I would like to understand a bit more if there are any issues you see with my DC output that could cause issue with an autotune problem I am having (sorry to hijack a bit).

this was my SSR

I am not an electric guru, just learning.
 
... it sounds like your SSR is faulty and is partially blocking the voltage.

the high amperage reading you have is a combo of the low-voltage problem (when you halve the voltage, the amperage requirement doubles; P=IxR; so its trying to make up for the lack of voltage by essentially requesting more amperage) and the fact that the pump is not spinning.
during the space of time between when power is first supplied, and when the pump reaches operating speed, the pump (or any motor) will pull much more than its normal operating amperage. since its never getting up to operating speed, its stuck in this startup mode pulling extra amperage and burning up the brushes and contacts on the motor....

That is pretty much what I was starting to think, a combination of low voltge and the normal starting current of a motor, causing the high amp readings.


...are your SSRs rated for switching 120v AC? you sure they arent DC? the components that control the main voltage (mosfets) are arranged differently for AC than for DC; because A/C alternates, A/C SSRs use two mosfets tied to the same source with different drains (as opposed to DC SSRs which use only one mosfet, or a more parrallel configuration). so it would make sense trying to pass 120v AC thru a DC SSR that you would get around half the voltage, as it would be blocking most of the current in one direction but not the other, effectively converting it into DC.

Good call on that one. That is a strong possibility.

To the OP... Do you have a link to your SSR source?

These are the ones I have tried so far. I also have a couple i got from auber ins somewhere I plan on trying.
http://www.amazon.com/gp/product/B005KPIX9A/?tag=skimlinks_replacement-20
 
Last edited by a moderator:
I posted this mostly to illustrate that teh DC output SSR didn't half my 240 intended AC output. Also I would like to understand a bit more if there are any issues you see with my DC output that could cause issue with an autotune problem I am having (sorry to hijack a bit).

this was my SSR

I am not an electric guru, just learning.
What you say about not halfing your 240v is not exactly true. The DC SSR will only allow 1/2 of the phase cycle to pass so you will still get a peak voltage of 240V but only for 1/2 the cycle. This will effectly 1/2 the power as power is only flowing for 1/2 the cycle.
What is the autotune problem you have?

My guess on why the DC SSR fried is because for 1/2 the time you were trying to shove 240V the wrong way through it.
 
What you say about not halfing your 240v is not exactly true. The DC SSR will only allow 1/2 of the phase cycle to pass so you will still get a peak voltage of 240V but only for 1/2 the cycle. This will effectly 1/2 the power as power is only flowing for 1/2 the cycle.
What is the autotune problem you have?

My guess on why the DC SSR fried is because for 1/2 the time you were trying to shove 240V the wrong way through it.

Quite possible.

The autotune issue I have is that when I went to autotune it, it passed the set point on the pid and went to a rolling boil and held it. On the PID, the auto read "0" for power on the automatic mode. However, it was a 100% boil. I cut the autotune out after waiting about 10-15 minutes and seeing no change in the boil strength. It never finished auto tune. I turne dautotune on at about 8degrees F below the set point. PJ was telling me I should have turned autotune on no with no more than 10F.

What bothered me was the reading of "0" for power on auto, yet full strength boil. I didn't take a reading with a multimeter, but it was evident the juice was flowing when it should have been off.

Currently I have a DC output ssr in the control panel. But plan to replace it soon, as I bought two replacement ac output SSRs. I left it in because I was brewing alot and had to wait for the replacement to arrive.
 
I had a similar issue when wiring a simple auber temp controller with a 120/240 v sir to control my freezer/lager chamber. I had the exact issues described. I ended up just using the internal auber relay because I could not get it to work properly. On your march pump in your setup, are they process controlled vs manual switching, hence the need for an ssr/relay?
 
flananuts said:
I had a similar issue when wiring a simple auber temp controller with a 120/240 v sir to control my freezer/lager chamber. I had the exact issues described. I ended up just using the internal auber relay because I could not get it to work properly. On your march pump in your setup, are they process controlled vs manual switching, hence the need for an ssr/relay?

I have processes set up for everything and all of my wiring and controls are hidden. That makes it difficult to run the pump manually.
 
the pictured SSR (if that is the same as yours) in the link is input dc output AC.

yea, that link is the same type of SSR i use (from light-object.com too). they are pretty cheap but ive had one die already, though it was probably from poor heat sinking on my end. i keep a spare around anyway, its only $8.

if yours actually is AC, then it could just have died. that thing i said earlier about AC SSRs using two mosfets- if one of the two mosfets died, you would have pretty much the same problems as using a DC SSR (meaning- you would see around half the voltage, as it would be blocked in one direction).

you may be able to read 120v with no load because even a dead mosfet will leak small amounts of current. but then when you go to try to pull more current, the voltage will drop like a rock. also- not all $7.99 walmart multimeters are capable of acurately reading strange voltages situations like these (half blocked, or irregular sine wave, or non-RMS ones). which would probably explain....
I accidentally bought output DC ssrs and they worked absolutely fine reading 238V as they should have on my system.
 
audger - You may be right on the meter, but I don't have a cheapo walmart one for 7.99 ;) Mine was probably more like a whopping $30-40 one if I remember right! ha


I tested mine before running with and without the element hooked up and still got 238v under a load. But that might be the meter.

Either way I know I am a quasi jackass for running it on the DC now. I have two ac out SSRs hanging out in my spare parts for my control panel. I will probably swap it out this coming weekend or next when I finish building my last pot for my system. I would like to baseline my setup and recalibrate my temp probes once I get everything up and running, and autotune, all at once. Seems like if I ever have enough time to test the system that means I have time to brew - you can guess which I end up doing over the other.


I temped my heat sink at 190F, even though it was rated for 40amps. Shortly after I put in a fan that blows across the fins and vents through the back, that seems to keep the heat down pretty good, though I haven't temped the sink with the fan on, because the way I mounted it requires the box to be closed (tapped in some brews on the top half of an auberins lid). But I can very comfortably touch the bottom of the box and feel warm, but not hot from the ssr. Before it was hot.
 
Back
Top