PERIODIC MAINTENANCE
Overload Protection
The machine is electrically protected from producing high output currents. Should the output current exceed
Thermal Protection
Thermostats protect the machine from excessive operating temperatures. Excessive temperatures may be caused by a lack of cooling air or operating the machine beyond the duty cycle and output rating. If excessive operating temperature should occur, the thermostat will prevent output voltage or current. The meter will remain energized during this time.
Thermostats are
Filter Capacitor Conditioning
A protection circuit is included to monitor the voltage across filter capacitors C1 and C2 (also C14 and C15 on 575 VAC units). In the event that the capacitor volt- age is too high, the protection circuit will prevent out- put. The protection circuit may prevent output provid- ing all these circumstances are met:
1.Machine is internally connected for 380 VAC, or higher input voltage.
2.Machine did not have power applied for many months.
3.Machine did not produce output when power was first switched on.
If these circumstances apply, the proper action is to switch the machine on and let it idle for up to 30 min- utes. This is required to condition the filter capacitors after an extended storage time. The protection circuit will automatically reset once the capacitor conditioning and resultant voltage levels are acceptable. It may be necessary to turn the power switch off and back on again after this period.
TROUBLESHOOTING
WARNING
ELECTRIC SHOCK can kill.
•Have an electrician install and service this equipment.
•Turn the input power off at the fuse box before working on equipment.
•Do not touch electrically hot parts.
EXPLODING PARTS can cause
injury.
• Failed parts can explode or cause other parts to explode when power is applied.
•Always wear a face shield and long sleeves when servicing.
Visual Inspection
Clean interior of machine with a low pressure airstream. Make a thorough inspection of all compo- nents. Look for signs of overheating, broken leads or other obvious problems. Many problems can be uncovered with a good visual inspection.
Open Circuit Voltage
The open circuit voltage of the Invertec
Test Conditions
Perform all testing at the lowest input voltage avail- able, except where a higher voltage is required by a test step. Make ohmmeter checks only after power has been disconnected from machine and after capacitors have been discharged.
Certain high voltage connections have been insulated with RTV sealant. It is necessary to break through the sealant with a sharp probe in order to make voltage or resistance checks.
Disconnect any control cables from remote control receptacle.
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