Maintenance - Mitsubishi Electric JR Series Instruction Manual

11. MAINTENANCE

The quality of maintenance will greatly affect the motor life.
(1) Inspection and maintenance schedule
a. Motors used sometimes, such as emergency motors or gate motors, absorb moisture during
the long-term suspension. This can cause the insulation resistance to drop. Therefore, daily
maintenance is required.
b. Recording of daily inspection, monthly inspections and disassembly inspections is helpful for
future maintenance.
c. Refer to Table 9 for the overhaul and inspection intervals.
Installation site
Dusty environment
Clean environment
(2) Daily inspections
a. Noise ........................... Prepare a sounding rod and listen to the noise from each motor section.
b. Odors ......................... Accidents can be sensed by a smell of varnish burning when the motor
c. Appearance ................. Check for oil leak, and check that the ventilation paths are not blocked.
(3) Monthly inspections
a. Deterioration or consumption of grease
................... Replenish or replace the grease according to the maintenance
b. Check that the insulation resistance is above the specified value. (1M or higher for the low
voltage motor.)
Do not touch the terminals with bare hands when measuring. Doing so could lead to electric
shocks.
c. Surface painting .......... Rust will form easily if the paint is peeled. Always repair the paint.
d. Adhesion of dust to air supply and exhaust opening: Abnormal overheat may be caused by poor
cooling.
e. When a drip-proof motor is used in a place with dust containing iron particles, cement particles,
sand particles and snow melting agent, it is necessary to overhaul the motor earlier (clean the
coils, and reapply varnish).
(4) Inspections and cleaning during disassembly
Check the operation state and make records before starting the overhaul. Use these records when
restarting operation after the overhaul.
a. Bearings ...................... Clean the bearings and bracket housing (bearing box), etc., and then
b. Coils and insulation ..... Check the wiring for looseness in the straps, and for adherence of dirt.
c. Other sections ............. Inspect the other sections and repair or replace the damaged parts.
d. Painting ....................... Repaint the motor if possible even if the paint is not peeling.
Table 9 Overhaul and inspection intervals
Used infrequently
Once every 1 to 2 years
Once every 2 to 3 years
Abnormal noise such as magnetic noise, mechanical noise,
mechanical friction noise and bearing noise can be detected.
overheats due to overloads or blocked ventilation.
If oil is leaking, the vibration may be significant. Check the vibration. (In
operating environment with large vibration, oil separated from
excessive grease in the bearings may leak to the outside.) Wipe away
oil with waste cloth. If the bearing temperature is high, check the load
(current value). However, in the case of lubricated bearings, a slight
leak of grease will not cause any problem if the bearing temperature is
normal. Even in the case of shielded bearings, an insignificant amount
of separated oil may leak at the initial stage, but this will not affect the
operation. Touching any part of the bearings or frame to check the
temperature is dangerous. Use a temperature measuring device, such
as an alcohol thermometer.
schedule. (Refer to 13-(4)(5).)
replace the grease. Refer to the Table 12 or "Initial greasing amount"
listed on the " Grease replenishment procedures" nameplate.
When shielded bearings are used, replace the bearings. Check the
dimensions of the bearing housing of the shaft (normally k5) and the
bearing housing of the bracket (normally H6), and, if the housings have
worn, replace them with new ones, or repair them by metal spraying.
Clean as required.
Clean any contaminated parts.
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Continuously used
Once every two years
Once every 3 to 5 years