# dc motor amp draw based on HP and watts

I repair treadmills and occasionally the motor causes the controller to fail. I use a 20v dc source with no load for the test.I have determined thru testing many motors of the same specs that a current draw above .75 amps will cause speed regulation issues and if it goes above 1 amp the controller may fail upon startup. A new motor will typically read .53-.60 amps. I also listen for bearing noise to eliminate that. My question is because I run into many motors I haven't tested and don't know what the "good reading should be can I determine that by any info off the label. Unfortunately some motors have only he HP and Wattage rating. For example the label says 2.8hp/2089 watts. Thanks in advance for your time to reply Jon

• 2.8hp is essentially 2089W (well 2088 but that 2.8hp is prob 2.801HP) Some people are use to reading in HP some in Watts – JonRB Aug 21 '15 at 10:47

$\Large I= \frac {P}{V}$
$Current (ampere) = \frac {Power (watt)} {Voltage (volt)}$