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©2020 Regal Beloit Corporation, All Rights Reserved. MCIM20001E • Form# SB0098E
• Check bearings for wear/damage – replace as
necessary.
• Check all bolts and nuts for cracks or damage –
replace as necessary.
• Check all holding down bolts for signs of fatigue or
damage – replace as necessary.
• After re-assembly, check and record in the log book -
Insulation resistance by megger
No load current and voltages
Full load current and voltages
Ensure that these figures compare well with the
original records in the log book.
• Check and ensure that the cooling fan is operational.
12.0 SEALED BEARINGS
The required replacement interval for sealed bearings is
generally determined by the grease life which is dependant
on operating temperature, operating speed, the limiting
speed of the bearing and the type of grease. Under normal
operating conditions the following relationship applies:
Where:
t
= Average grease life (hours)
n
= Speed (RPM)
N
= Bearing limiting speed with grease lubrication
(RPM)
T
= Operating temperature (°C)
For further information, please contact Regal Australia
for advice
(please see page 4 for the contact details).
12.1 OPEN (REGREASABLE) BEARINGS
It should be noted that for motors fitted with ball and roller
bearings, the lubrication intervals for both bearings should
be based on the roller bearing data.
The re-lubrication intervals recommended are calculated
on the basis of normal working conditions.
Replenishment of grease media should be by means of a
hand held grease gun whilst motor is running with relief plate
removed. Air operated grease guns should not be used.
12.2
LOADABILITY CURVE FOR VVVF DRIVE
1. Applied load on the motor shall be within the limits for the
loadability curve for the motor. The standard loadability
curve is shown below. In special circumstances,
determined by Regal, the limits on the curve may be
extended.* In either case the limits of operation are
specified on the motor Pulse Width Modulation (PWM)
Converter Supply nameplate.
2. PPA and PPC Ex nA motors are suitable for operation
with PWM converters (VVVF drives) with carrier
frequency >5kHz or default switching frequency of the
drive whichever is lower.
3. When motors are operated below 50Hz with variable
torque loads, a de-rating factor is to be applied as per
the solid line (curves 1 & 3) of the loadability curve.
4. When motors are operated below 30Hz with constant
torque loads (curve 2) forced ventilation by separately
driven cooling fan is required. Alternatively, permissible
maximum torque at lower frequencies is to be
determined by test for self cooled motors. In special
circumstances the lower limit of operation may be a
frequency less than 30Hz. This will be specified on the
motor PWM Converter Supply nameplate
5. At frequencies above 50Hz the motor are suitable
for operation at constant power up to the maximum
frequency shown on the nameplate (curves 4 & 5). All
motors are suitable for operation up to 60Hz. Maximum
frequency is specified on the nameplate.
6. These motors supplied by VVVF drives must be fitted
with thermal protection devices, such as thermistors in
winding, which shall be connected to the motor control
circuit in such a manner as to prevent the nominated
temperature class from being exceeded.
Extended Limits on loadability curve for the motor may be
calculated or determined by testing. Testing is performed
subject to charges.
