Hello!

I am using a LabJack to control two 12 volt 1.5 amp motors. In order to do this, I will need to connect a relay in-between the LabJack and the motor. The output of the LabJack is a maximum of 5 volts at 20 mA. My question: what relay will work?

If possible, I would prefer to use a solid-state relay to a mechanical one simply because of the arcing problem, which can cause problems in the computer and the LabJack. However, they are quite expensive.

I could use the cheaper mechanical relay only I don’t know how to stifle the arcing.

What do you recommend?

Thanks!

 

You did not mention if the motor runs on AC or DC.
Lets assume you meant DC. The solid state relays are usually only for AC switching as they switch on zero crossing though I dare say there are DC versions, even more expensive, available.
If your motor runs on DC you can try a reverse biased diode across its connection to suppress the arcing at the relay contacts.
You should also put a reverse bias diode across the relay coil to protect the computer driving it from the back EMF generated spikes.

Klaus