Lincoln Electric IM597 manual RELAY K2 OPERATION, Testing The Input Power Circuits, 24.0

8.1.2 TESTING THE POTENTIOMETER - “W” CLOCKED

Using the torch amphenol, check the resistance across pin “D” (wiper) and pin “C”. The resistance should vary from 0 - 5K ohms.

Check the resistance across pin “D” (wiper) and pin “G”. The resistance should vary from 5K - 0 ohms.

8.1.3 TESTING THE MICRO SWITCH

Using the torch amphenol, check for continuity across pins “E” and “F” when the trigger is pressed.

8.2 RELAY K2 OPERATION

When the torch trigger is pressed, 24VAC is sent to the coil of relay K2. When K2 is energized, AC is sent to the slave motor, spool brake, and the AC contactor. Relay K2 is also responsible for sending 24VAC to the speed control circuit and shorting the torch motor leads together when the trigger is released for the dynamic braking system. K2 also provides the closing contactor signal.

8.3 TESTING THE INPUT POWER CIRCUITS

The AC circuits are protected by fuses F2 and F3. If F2 and F3 continually blow, remove J4 (Brake Solenoid), J7 (slave motor) and J5-3,4 (AC Contactor) from the P.C. Board. Replace fuse, and retrigger system. If fuse does not blow; isolate the problem by plugging in J4, J7, and J5-3,4 one at a time until the fuse blows.

8.4 TESTING THE SPEED CONTROL

NOTE: The torch should be tested first and the amphenol must be connected to the

Cobramatic® to perform this test.

Place a voltmeter across diode D10 and press torch trigger. A reading of 0 - 24VDC should be observed, as the torch potentiometer varied.

	24.0
D10	VDC
	+	_

K1587-1 Cobramatic® Owner's Manual - Page 15