Welding Performance - Lincoln Electric 10501 Operator's Manual

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Table Of Contents

Table of Contents

B-6

THERMAL SHUTDOWN

This welder has thermostatic protection from exces-

sive duty cycles, overloads, loss of cooling, and high

ambient temperature. When the welder is subjected to

an overload or loss of cooling, a thermostat will open.

This condition will be indicated by the illumination of

the yellow Thermostatic Protection Light on the case

front (see figure B.1). The fan will continue to run to

cool the power source. No welding is possible until the

machine is allowed to cool and the Thermostatic

Protection Light goes out.

OVER CURRENT PROTECTION

SHUTDOWN

Average Current Shutdown

To protect the SCRʼs , the DC-655 will shut down to

essentially no output if the output current averages

over 900 amps for about 5-6 seconds, and in less

than 0.3 seconds if averaging over 1200 amps (short-

er time for higher current). Control PC board LED4,

shutdown light, will turn on.

This average current shut down can only be reset by

opening the feeder gun trigger, or switching the DC-

655 Output/Remote switch out of the "on" position.

Peak Current Shutdown

To protect the SCR;s, the DC-655 will shut down

immediately to essentially no output if the peak output

current exceeds 2500 amps (about 1800A average).

Control PC board LED4, shutdown light, will turn on.

This peak current shut down can be reset by turning

the DC-655 input power off, then on.

REMOTE CONTROL LEADS FAULT

PROTECTION SHUTDOWN

The remote control leads from the 14-pin receptacle

or terminal strip are protected against high voltage

faults to the electrode circuit or auxiliary voltage sup-

plies. If such a fault occurs the DC-655 will shut down

the input primary voltage to the transformer to prevent

the fault output. Control PC board LED3, input shut-

down light, turns on.

If this input shutdown occurs the input power pilot light

remains lit, since the power switch is ON and control

power is still present. Welding output or auxiliary sup-

ply output will not be present

This input shut down is reset by turning the DC-655

input power off, then on. If the fault is not corrected

however, the shutdown will re-occur when turning on

the input power.

OPERATION

SHORTED RECTIFIER FAULT

PROTECTION

If a short occurs across one of the silicon controlled

rectifiers of the DC-655, a potentially hazardous AC

voltage could appear across the welding output termi-

nals, even in idle mode when no output should be pre-

sent. If such a fault occurs the DC-655 will shut down

the input primary voltage to the transformer to prevent

the fault output. Control PC board LED3, input shut-

down light, turns on.

If this input shutdown occurs the input power pilot light

remains lit, since the power switch is ON and control

power is still present. Welding output or auxiliary sup-

ply output will not be present

This input shut down is reset by turning the DC-655

input power off, then on. If the fault is not corrected

however, the shutdown will re-occur when turning on

the input power.

IDLE SHUT DOWN TIMER

For additional operating economy, the DC-655 can be

set up to automatically shut off the primary input

power to the main transformer after a selectable time

(1/2 or 2 hr.) has expired without welding. The unex-

pired timer is reset with each weld.

The idle mode timer is activated by setting Switch #1

(left most) of the DIP Switch located on the lower-cen-

ter of the DC-655 Control PC board. from the down

(Off) position to the up (On) position. Setting Switch

#2 of the DIP switch to up (On) sets the shutdown

time to 2 hours. Setting Switch #2 of the DIP switch to

down (Off) sets the shutdown time to 1/2 hour. Shut

down is reset by turning the DC-655 input power off,

then on.

Note: