Power Required To Start A Motor; How Much Power Can The Generator Supply - Miller Bobcat 250 Application Manual

8. Power Required To Start A Motor

4
1
VOLTS
3
CODE
HP
Single-Phase Induction Motor Starting Requirements
Motor Start
Code
KVA/HP
EXAMPLE: Calculate the starting amperage required for a 230 V, 1/4 HP
motor with a motor start code of M.
Volts = 230
11.2 x 1/4 x 1000
230

9. How Much Power Can The Generator Supply?

AC MOTOR
230 AMPS
M Hz
1/4 PHASE
G H
6.3 7.1
kVA/HP x HP x 1000
VOLTS
HP = 1/4 Using Table, Code M results in kVA/HP = 11.2
= 12.2 A
Starting the motor requires 12.2 amperes.
1
2
2.5
60
1
J K L
8.0 9.0 10.0
= STARTING AMPERAGE
2
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 start-
ing amperage.
Step 2: Find Motor HP and
Volts.
Step 3: Determine starting
amperage (see example).
Welding generator amper-
age output must be at least
twice the motor's running
amperage.
M N P
11.2 12.5 14.0
1 Limit Load To 90% Of
Generator Output
Always start non-resistive
(motor) loads in order from
largest to smallest, and add
resistive loads last.
2 5 Second Rule
If motor does not start within
5 seconds, turn off power to
prevent motor damage. Mo-
tor requires more power than
generator can supply.
803 636 / S-0625
S-0624
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