Miller Electric PRO 300 11-8. Power Required To Start Motor, 11-9. How Much Power Can Generator Supply?

OM-4422 Page 57
11-8. Power Required To Start Motor
Single-Phase Induction Motor Starting Requirements
Motor Start
Code G H J K L M N P
KVA/HP 6.3 7.1 8.0 9.0 10.0 11.2 12.5 14.0
S-0624
1 Motor Start Code
2 Running Amperage
3 Motor HP
4 Motor Voltage
To find starting amperage:
Step 1: Find code and use table to
find kVA/HP. If code is not listed,
multiply running amperage by six to
find starting amperage.
Step 2: Find Motor HP and Volts.
Step 3: Determine starting amper-
age (see example).
Welding generator amperage out-
put must be at least twice the
motor’s running amperage.
(kVA/HP x HP x 1000) / Volts =
Starting Amperage
Example: Calculate starting amper-
age required for a 230 V, 1/4 HP mo-
tor with a motor start code of M.
Volts = 230, HP = 1/4, kVA/HP =
11.2
(11.2 x 1/4 x 1000) / 230 = 12.2A
Starting the motor requires 12.2
amperes.
VOLTS AMPS
HP
230 2.5
1/4
Hz
PHASE
CODE 60
1
M
AC MOTOR
12
3
4
11-9. How Much Power Can Generator Supply?
Ref. ST-800 396-A / S-0625
1 Limit Load To 90% Of
Generator Output
Always start non-resistive (motor)
loads in order from largest to small-
est, and add resistive loads last.
2 5 Second Rule
If motor does not start within 5
seconds, turn off power to prevent
motor damage. Motor requires
more power than generator can
supply.
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2