I am on a senior design team at school. We have designed a mechanical system that uses a DeWalt 20V drill motor to drive the system. It is powered by the stock lithium ion batteries. I need to implement a few limit switches. I think 4 will do the trick, two of them will be SPST and two will be SPDT. I ran some tests with an ammeter and found the drill is pulling 17 amps without a load. When loaded, there were a few 100 amp spikes. What limit switches can I use that will handle this sort of power? (I am assuming 20 V * 100 Amps = 2000 Watts) I need them to have a fairly small footprint. Is this even possible to accomplish? Thanks in advance for any help.
I have added a wire schematic, maybe this can help. It was a bit dicey how I measured the current. I pulled the battery out of the drill, and completed the connection with wire and an ammeter to get power to the drill from the battery which was laying on a table. It was crude, but the motor came on, and the ammeter spit out a reading.
Best Answer
Limit switches don't have to carry all the current, but they can drive a relay that can! I'd go for a normally open relay, with limit switches designed to close the relay when all is good -- this gives a better failure mode (motor off!) if things malfunction. It's probably not as ideal as a direct cut of current to the motor through your switch, but it should get the job done safely.
Think hard about all your failure modes as you go through this exercise!