OM-4433 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
1
2
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.
1
2
