Mitsubishi Electronics FR-A500L Insulation resistance test using megger, Dielectric strength test

PROTECTIVE FUNCTIONS

5.3.4 Insulation resistance test using megger

1)Before performing the insulation resistance test using a megger on the external circuit, disconnect the cables from all terminals of the inverter so that the test voltage is not applied to the inverter.

2)For the continuity test of the control circuit, use a tester (high resistance range) and do not use the megger or buzzer.

3)For the inverter, conduct the insulation resistance test on the main circuit only as shown below and do not perform the test on the control circuit. (Use a 500VDC megger.)

	R<L1> Inverter		Motor
Power		U
	S<L2>	V	IM
supply
	T<L3>	M

DC500V megger

Ground terminal

5.3.5 Dielectric strength test

Do not conduct a dielectric strength test. The inverter's main circuit uses semiconductors, which may be deteriorated if a pressure test is made.

Daily and Periodic Inspection

Area of				Interval
	Inspection			Periodic
Inspec-		Description				Method	Criterion		Instrument
	Item		Daily	1	2
tion
				year	years
							Ambient
							temperature:
		Check ambient					10 C to +40 C,		Thermometer,
	Surrounding						− °	°
		temperature, humidity,	{			(Refer to page 3)	non-freezing.		hygrometer,
	environment	dust, dirt, etc.					Ambient humidity:		recorder
							90% or less,
General							non-condensing.
	Overall unit	Check for unusual	{			Visual and auditory	No fault.
		vibration and noise.				checks.
	Power					Measure voltage	Within permissible
							AC voltage
		Check that main circuit				across inverter			Tester, digital
	supply		{
							fluctuation
		voltage is normal.				terminals R-S-T			multimeter
	voltage
							(Refer to page 40)
						<L1-L2-L3,>.
		(1) Check with megger		{	{	(1) Disconnect all	(1) 5M Ω	or more.
		(across main circuit				cables from	(2), (3) No fault.
		terminals and				inverter and
		ground terminal).				measure across
		(2) Check for loose		{		terminals R, S, T,			500VDC class
	General	screws and bolts.				U, V, W <L1, L2,
		(3) Check for overheat-		{		L3, U, V, W>, and			megger
		ing of each part.				ground terminal
Main		(4) Clean.				with megger.
						(2) Re-tighten.
circuit
						(3) Visual check.
		(1) Check conductors		{		(1), (2) Visual check.	(1), (2) No fault.
	Conductors,	for distortion.
		(2) Check cable		{
	cables	sheaths for
		breakage.
	Terminal	Check for damage.		{		Visual check.	No fault
	block

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