

If something in the system is not unloading then you could be trying to drive high pressure with a low pressure pump. The high pressure may use 20HP at 3,000PSI and the low pressure 20HP at 1500PSI. Lets say both a high volume (low pressure) and a high pressure (low volume). Hydraulic pumps often have multiple pumps in one unit. I'm going to go out on a limb here and guess that your motor is stalling at some point. Your system could be rated for 15HP, but they put a 20HP motor on. You need to know what the maximum pressure at the motor/pump's RPM to calculate maximum horsepower required. Horsepower is related to pump GPM and pressure. If your meter were to show 12.5A then you are utilizing 10HP. So, if you have a 20HP motor with a nameplate FLA of 25A, and your meter is reading 25A, then you are pulling 20HP. There is a direct relation to HP and FLA assuming RPM and voltage stays constant.
