Overload Protection, Auxiliary Power, Operation

B-7

OPERATION

Return to Section TOC

Return to Master TOC

OVERLOAD PROTECTION

The power source is thermostatically protected with proximity thermostats against overload or insufficient cooling. One thermostat is located on the nose of the center bottom primary coil and a second thermostat is attached to the lead connecting the secondaries. Both thermostats are connected in series with 2-4 circuit. If the machine is overloaded, the primary thermostat will open, the output will be zero, the amber thermal pro- tection light will be on and the fan will continue to run. The secondary thermostat will open either with an excessive overload or insufficient cooling. The output will be zero, the amber protection light will be on and the fan will continue to run. When the thermostats reset, the protection light will be off.

The power source is also protected against overloads on the SCR bridge assembly through the solid state fault protection circuit. This circuit senses an overload on the power source and limits the output to approxi- mately 550 amps by phasing back the SCR’s.

Protection is provided to protect the circuitry from acci- dental grounds. If leads 75, 76, or 77 are accidentally “grounded” to the positive output lead, the output will be reduced to a low value, thus preventing any damage to the machine. If the ground occurs between 75, 76, 77 and the negative output lead, one of the PC board elec- tronic “self-restoring” fuses will blow, preventing any machine damage. After the ground is cleared, the fuses automatically reset within a few seconds.

AUXILIARY POWER

On machines above code 9400, the IDEALARC CV- 400 can provide nominally 115 volts AC and 42 volts AC auxiliary power for operating wire feeding equip- ment and other accessories. This power is available at the 14-pin amphenol on the control panel and/or at the terminal strip behind the hinged control panel on the case front. On the amphenol, 115 volts AC is available at pins A and J (Domestic and Export models only); 42 volts AC is available at pins I and K. On the terminal strip, 115 volts AC is available at terminals 31 and 32; 42 volts AC is not available at the terminal strip. The two circuits, 115 volts AC and 42 volts AC, are isolated; and each is protected by a 10 amp circuit breaker.

FRONT VIEW OF 14-PIN CONNECTOR

RECEPTACLE

	K=42
A=32	J=31
B=GND	I=41
L	N
C=2	H=21
D=4	G=75
E=77	F=76
	M

PIN	LEAD NO.	FUNCTION
A	32	115 VAC
B	GND	Chassis Connection
C	2	Trigger Circuit
D	4	Trigger Circuit
E	77	Output Control
F	76	Output Control
G	75	Output Control
H	21	Work Connection
I	41	42 VAC
J	31	115 VAC
K	42	42 VAC
L	---	---
M	---	---
N	---	---

IDEALARC CV-400

Lincoln Electric SVM136-A Overload Protection, Auxiliary Power, Operation, Return to Section TOC

Models: SVM136-A

OVERLOAD PROTECTION

AUXILIARY POWER

LEAD NO.

FUNCTION