suggest solid state part or circuit for control of aquarium pump?

Thread Starter

tom walter

Joined Mar 3, 2018
4
Hi, I have an non-submersible aquarium pump (Eheim 1046) that runs off 120VAC. It draws only 66mA after it starts. I've been controlling it via a 12VDC mechanical relay but I would rather use something more dependable like an SSR. For many of the SSRs I looked at, the minimum load current is 100mA or above.

So can anyone point me in the right direction? I need 12VDC control voltage and it needs to turn on and stay on while the pump draws 66mA. Something ready to go on a board or in a puck would be nice, but I didn't have much luck searching eBay.
 

Thread Starter

tom walter

Joined Mar 3, 2018
4
I found it. The secret was that the lower-capacity SSR's come in a SIP package and there seems to be plenty.
The Crydom MP series seems to fit the bill. Nothing found ready-to-go on a board however.
 

ebp

Joined Feb 8, 2018
2,332
If the pump is one of the vibrator types, be aware that the load is very inductive - much more-so than a motor. This can cause issues with some SSRs at turn-off. The data sheets may be helpful, though as I recall Crydom data sheets used to be nearly useless.
At such low current a simple resistor-capacitor snubber should be quite adequate. Motorola published some useful info on snubbers in their ap notes for opto-triac couplers (MOC30xx series). I don't know if ON still publishes the ap notes. ON also acquired Fairchild which made similar couplers and published ap notes.
Any discussion of snubbers for triacs with inductive loads will guide you.
 
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