11-8. Power Required To Start Motor
Single-Phase Induction Motor Starting Requirements
Motor Start | G | H | J | K | L | M | N | P | |
Code |
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
KVA/HP | 6.3 | 7.1 | 8.0 | 9.0 | 10.0 | 11.2 | 12.5 | 14.0 | |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4 |
|
|
|
|
|
|
| AC MOTOR |
| 2 | |||
1 |
|
|
| |||
| VOLTS | 230 | AMPS | 2.5 | ||
|
| |||||
3 |
| CODE | M | Hz | 60 |
|
|
| HP | 1/4 | PHASE 1 |
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1Motor Start Code
2Running Amperage
3Motor HP
4Motor 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.
11-9. How Much Power Can Generator Supply?
1
2
1Limit Load To 90% Of Generator Output
Always start
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.
Ref.