1. On the motor drive PCB:
Note: The PCB  on the HPC-1K has a fan. The HPC-300 PCB  does not.
Make sure that the circuit breaker is in the ON position.
If the circuit breaker has tripped, turn it back on. Test the HPC system. If the circuit breaker trips again, check for a short circuit in the HPC pump.
Note: You must use water-based coolants with the HPC-1K system. Thicker fluids like cutting oil will overload the pump and trip the breaker.
2. Check the pump for shorts:
Measure the (3) leads  to ground  on the HPC power cable. If all leads test open to ground, the pump and cabledo not have a short.
If the motor lead test indicates a short, disconnect the cable from the motor. Measure the (3) cable leads  to ground. If any lead tests short, the pump is at fault. If none of the leads test short, the cable is at fault.
3. If all leads test OK:
Check the HPC motor for binding that could cause an over amperage condition.