MGM
17
MGM motor running on Inverter Duty (Frequency Converter)
GENERAL CHARACTERISTICS
Class
Rated speed (RPM)
Effective maximum values of vibration speed (mm/s) depending on frame size H
56 mm
≤
H
≤
132 mm
132 mm
<
H
≤
225 mm
225 mm
<
H
≤
400 mm
Balancing
MGM brake motors are balanced with a half key applied to the motor shaft ends, according to the EN 60034-14. Reducing
vibrations is important both to avoid motor damage, especially to the bearings, and to avoid damage to the machinery to which
the motor is coupled. It is advisable to balance the parts of the attached machinery (the coupling, the pulleys, etc.) in order to
avoid vibrations. The maximum permissible vibration intensities for different frame size, according to the norm EN 60034-14,
can be seen in the table below. As standard motors are supplied with normal class balancing, upon request they can be supplied
with reduced or special class balancing.
The interference generated by electronic power devices such as inverters, can influence equipment sensitive to interference, such
as computers, load cells, photocells, temperature regulators, magnetic intrusion switches, or capacitance grounding circuits, and
control wiring.
Whenever it is necessary to reduce the interference caused by the inverter the following practical suggestions should be implemented.
Disturbances are highest nearby the inverter, and can be attenuated by increasing the distance. Sensitive devices should be kept
at least 50 cm from the frequency converter. The power wiring should be kept at least 50 cm away from the control wiring. Use
power cables as short as possible. Power cables longer than 10 m is a strong source of disturbances, and can cause malfunctions.
An EMI filter may be necessary on the power supply line.
Information on the correct wiring of the inverter to the motor to reduce the interference should be obtained from the inverter
manufacturer.
Noise
The noise of a running electric motor is mainly generated by the magnetic field, the bearings and the cooling system. The most relevant
noise level is generated by the cooling fan. Technical data sheets report the values of the sound pressure in dB (A) according to ISO
1680. The above mentioned values should be increased by about 3-4 dB on motors operating at 60 Hz. On request it is possible to
provide motors with low noise level. During the braking action the noise level depends on the air gap (distance between the brake coil
and the brake moving element). Periodic air gap adjustment provides lower noise levels.
N (Normal)
R (reduced)
S (Special)
600
≤
n
≤
3600
600
≤
n
≤
1800
1800 < n
≤
3600
600
≤
n
≤
1800
1800 < n
≤
3600
0.71
1.12
0.45
0.71
1.8
0
1.12
1.8
0
0.71
1.12
2.8
0
1.8
0
2.8
0
1.12
1.8
0
3.5
0