|
Scratch_6057
Apprentice Modder
GA
USA
56 Posts |
 Posted - 09/15/2006 : 07:04:59
|
If you are evaluating motors / doing motor testing and you want to
determine how many Amps a motor draws under load, the thing
to do is to use a LOW Resistance HIGH Wattage SHUNT as
shown in the picture.
The Resistors (R1, R2) are 1 Ohm 25 Watts each, wired in parallel
for a total of 0.5 Ohm 50 Watts. (mine actually came out 0.6 ohms)
These resistors cost $0.99 each. Measure the VOLTAGE across the
RESISTORS (points A, B) and divide that voltage by the resistance
of the resistor pair to obtain a current thru the ENTIRE circuit.
In my particular case, with 12 volts applied to the circuit
1.76 Volts (across resistors)
/ 0.60 Ohms (measured resistance of the pair)
-------------------------------------------------------------
2.866… (amps thru the circuit) No Load
As you increase the load on the motor, you’ll see the current increase.
I wasn’t thinking the other day, (in a hurry) set the meter to read AMPS
and placed the meter in series with the motor. Loaded the motor down,
read a 47 Amp peek and blew an $11.00 fuse in the meter (20 amp, 600 Volt)
BUMMER! Not only was the fuse expensive but it was hard to find locally.
4.71 KB |
Edited by - Scratch_6057 on 09/15/2006 07:10:27 |
|
FAQ - Reading Motor Amps (Current)
Forum Locked
Topic Locked
