Miller Electric Big Blue 402P Power Required To Start Motor, How Much Power Can Generator Supply?

12-8. Power Required To Start Motor

4		AC MOTOR			2
1
	VOLTS	230	AMPS	2.5
3	CODE	M	Hz	60
	HP	1/4	PHASE 1

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

kVA/HP x HP x 1000

= STARTING AMPERAGE

VOLTS

EXAMPLE: Calculate the starting amperage required for a 230 V, 1/4

HP motor with a motor start code of M.

Volts = 230

HP = 1/4 Using Table, Code M results in kVA/HP = 11.2

11.2 x 1/4 x 1000

= 12.2 A

Starting the motor requires 12.2 amperes.

230

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.

S-0624

12-9. How Much Power Can Generator Supply?

1

2

1Limit 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.

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

Return To Table Of Contents OM-491 Page 59