dc motor amp draw based on HP and watts
Horsepower (hp) is a unit of measurement of power. The mechanical horsepower, also known as imperial horsepower, of exactly 550 foot-pounds per second is approximately equivalent to 745.7 watts. 

The equation is

\$ \Large I= \frac {P}{V}\$

\$ Current (ampere) = \frac {Power (watt)} {Voltage (volt)}\$