Hello Guys, today i got a stepper-board for my cnc-project im building at the moment and i have one question.
That stepper-board has 3 relays "htv 6-dc12v-sh" on it.
They are rated with 5A 250V. Am i right if i think that its possible to connect maximum 1250Watt to that relay-type? I want to connect the spindle there that has 150Watt at the moment and i dont want to burn the board ...
Its not really arduino-specific but the board is driven by one..

Thanks for your help.

I would not use it to switch at full current rating. I would use it at up to 3A resistive.

If using it for a motor, remember that the starting current can be 10 times the running current. If you use it at 5A, your contacts will burn out quicker.


Is there any hint how i could avoid burning it? What kind of "electronic switch" could i use to automatic-enable the spindle.
The spindle has "only" around 120-140Watt at the moment and i think that would be at maximum speed of that dc-motor. So if you say 3A at 220V should be 660Watt if i calculate the right way.

Is there any hint how i could avoid burning it?

Use that relay to control a higher contact current relay, perhaps? Also - make sure that the secondary relay is rated (the contacts) for continuous inductive loads (relay contacts are designed to control resistive, inductive, and capacitive loads - and for intermittent vs. continuous usage - read the datasheet for the relay needed).

Is your spindle an induction motor or a universal motor? Universal motors are generally
less inductive, but you do need to find the inductive rating of the relay and you will need
a suitable snubber network I think.