Miller Electric Big Blue 251D Description Of Front Panel Controls See Section, Remote A/V Control

6-2. Description Of Front Panel Controls (See Section 6-1)

. This unit has a max OCV control circuit			(See Section 6-3)
	that resets the Amperage/Voltage Con-	6 Magnetic Shutdown Switch (Optional)
	trol to maximum when the arc breaks.	Use switch during start-up to bypass optional
	When an arc is struck, weld output control	engine shutdown system. System stops en-
	returns to the front panel or remote con-	gine if oil pressure is too low or oil temperature
	trol setting. The Amperage/voltage Con-	is too high.
	trol adjusts amperage only when welding	7	Engine Control Switch
	and does not adjust open-circuit voltage.	To Start: turn switch to Start while pressing
1	Ampere Range Switch
		Shutdown switch. Release switches when
Use switch to select weld amperage range.		engine starts.
For most welding applications, use lowest		. If the engine does not start, let engine
amperage range possible to prevent arc out-
ages.			come to a complete stop before attempt-
Y Do not switch under load.			ing restart.

Light goes on if oil pressure is too low. If unit has automatic shutdown option, light also goes on if oil temperature is too high.

YStop engine and fix trouble if either light goes on.

10 Ether Starting Aid Switch (Optional)

Push switch up and release while cranking engine to release ether.

YDo not use Ether if engine is running.

11 Engine Hour Meter

12 Oil Temperature Gauge/Switch

(Optional)

2 Amperage/Voltage Control

Control adjusts amperage within range selected by Ampere Range switch. Weld out- put would be 148 A DC with controls set as shown (50% of 95 to 200 A).

3DC Voltmeter (Optional)

4DC Ammeter (Optional)

5Remote A/V Switch And Receptacle

In Run position, engine runs at weld/power speed. In Run/Idle position (optional), engine runs at idle speed at no load and weld/power speed with load applied.

To Stop: turn switch to Off position.

8 Battery Charging Warning Light

Light goes on when battery is not charging.

9 Oil Pressure Warning Light

13	Oil Pressure Gauge/Switch (Optional)
14	Polarity Switch (Optional)

Place switch in Straight position for electrode negative, or Reverse position for electrode positive.

15 Manual Shutoff Lever

Use lever to stop engine if engine control switch does not work.

6-3. Remote A/V Control

1 A/V Control Switch

Use switch to select front panel or remote amperage control.

2 Remote A/V Receptacle RC3 Connect optional remote control to

1 2 RC3.

Example: Combination Remote Amperage Control

In Example:

Range = 95 to 200 A

Percentage Of Range = 50%

Max = 148 A DC (50% of 95 to 200)

			Max (148 A DC)
			Min (70 A DC)
Set Switch	Set Range	Set Percentage	Adjust Optional Remote Control
			S-0774

OM-480 Page 19