Installation; Msc-3 Mounting Location; Caution Installation Information - Zener MSC-3 Instruction Manual

Installation

MSC-3 mounting location

In general, the MSC-3 should be mounted as close to the motor as practical, consistent with other
requirements. This is not an absolute requirement, but the following advantages may support such a
choice:
• Generally, electrical cabling costs per metre are lower for the unscreened power cable used on the
AC supply side than for the screened output cable required between the MSC-3 and the motor.
Cabling costs can therefore be expected to be lower when less screened cable is needed.
• EMC performance can be expected to be mildly enhanced with a shorter motor cable because of
reduced leakage from the cable
• In circumstances where an isolator switch is required near the motor, it may be possible to
connect this in the AC supply to the MSC-3. This has the advantages of saving two screened
cable terminations and allowing the use of a non-metallic isolator switch enclosure where allowed
by local electrical codes. There are also safety advantages for service personnel in that the local
isolator switch also isolates the MSC-3 from the electrical supply.
The choice is predominantly an economic one. There are many perfectly satisfactory installations where,
for a variety of specific site reasons, the most effective solution results in the MSC-3 and the motor
being a long distance apart.

CAUTION Installation Information

• The MSC-3 must be mounted on a vibration free vertical surface, away from heat radiating
sources. Do not mount the MSC-3 in direct sunlight or on a hot surface.
• The MSC-3 must be mounted vertically. No other mounting orientation is acceptable.
• If the MSC-3 is mounted inside another enclosure, the total heat dissipation and resulting
temperature rise in the enclosure must be allowed for.
• Attention is drawn to the potential for condensation in vulnerable environments. Additional
precautions may be required for all enclosure types.
• The installation location and environment should provide for safe access and working conditions
for service personnel. Do not mount the MSC-3 in "confined spaces"
• Do not drill holes in the enclosure except in the gland plate.
• Remove the gland plate before drilling cable holes.
• Do not allow metal shavings or any other conductive material to enter the enclosure or damage
may result.
• DC Bus choke is mandatory with MSC-3Jxx (600VAC) and some other models.
• The optional DC Bus choke is fitted inside the MSC-3 in all models except Chassis A, IP30. For
these models, the DC Bus choke is located in an additional enclosure fitted to the rear face of the
MSC-3. The wiring between the MSC-3 and the choke is internal.
DC bus chokes
MSC-3 may be fitted with an optional DC bus choke. Fitting this option offers several benefits:
• Considerable reduction in harmonic and RMS currents in the AC line, particularly on low
impedance (high fault level) electrical supplies. Values become relatively independent of AC line
parameters, simplifying application design.
• Increased tolerance to phase imbalance in the 3 phase AC supply.
• Increased immunity to AC line transients.
1. Confined spaces are generally defined in Occupational Health and Safety (OH&S) regulations to mean spaces
where special precautions are necessary to ensure a safe breathing atmosphere, or there is limited access for
escape/rescue in case of emergency.
IM00120 IM00120
MSC-3 Instruction Manual
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