Miller Electric 400P, 500 X Power Required To Start Motor, How Much Power Can Generator Supply?

12-8. 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.

S-0624

12-9. How Much Power Can Generator Supply?

1 Limit Load To 90% Of

Generator Output

1

2

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.

Ref. ST-800 396-A / S-0625

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