YASKAWA FSDrive-MV1000 Instructions Manual page 164

6.2 Periodic Inspection
Carry out periodic inspections in the manner described below.
Megger Check (Measurement of Insulation Resistance)
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Measure Insulation Resistance of the Drive Primary Circuit
Use a 1000 V Megger insulation resistance tester.
The measured insulation resistance must be 30 MΩ or more.
As the primary circuit is grounded at high-resistance for input voltage detection, disconnect the wiring to the voltage
detection resistor before measuring insulation resistance.
Measure Insulation Resistance of the Drive Secondary Circuit (Motor Side)
Use a 1000 V Megger insulation resistance tester.
The measured insulation resistance must be 2 MΩ or more.
The secondary circuit is grounded at high-resistance for output voltage detection and ground-fault detection. Disconnect
the high-resistance resistor for voltage detection and Power Cell output cables connected to the output terminals before
measuring insulation resistance.
Measure Insulation Resistance of the Surge Absorber
Use a 1000 V Megger insulation resistance tester.
The measured insulation resistance must be 1000 MΩ or more.
Note: Make sure that the surge absorber has been removed from the circuit.
Screws, Bolts, and Connectors
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Looseness in the wiring connections of the main circuit cable could lead to fire due to overheating of the connections.
During periodic inspections, be sure to retighten the screws and bolts, and to reinsert the connector securely. For the
tightening torque of the screws and bolts, refer to the following recommendations.
• M8 bolts: 8.9 N m to 10.8 N m
• M10 bolts: 18 N m to 23 N m
• M12 bolts: 31.5 N m to 39.5 N m
• M16 bolts: 78.5 N m to 98 N m
Check the following items.
• High-voltage input terminals, high-voltage output terminals
• Input voltage detection circuit (option), output voltage detection circuit
• Transformer primary terminals/primary voltage tap terminals
• Transformer secondary terminals
• Power Cell I/O terminals and optical fiber cable connector
• Power Cell screws, bolts, and connectors
• Control power supply input terminals
• Control transformer I/O terminals (option)
• Power relay I/O terminals for cooling fans
• Screws, bolts, and connectors of each control board
• Control I/O terminals
Transformer
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Check the following items.
• Check for anything abnormal in the external appearance.
• Check for discoloration indicating burn marks.
• Check for accumulated dirt or dust.
If you find any, clean it away.
• Check for loose bolts in the I/O terminals and tap terminals.
If there are any, retighten them with the stipulated tightening torque.
164 YASKAWA ELECTRIC EZZ010928 FSDrive-MV1000 Instructions