How To Connect Motor-Introduction; Cable Length And Cross-Section; Switching Frequency; Terminals For Motor Connection - Trane TR200 Instruction Manual

Electrical Installation
How to Connect Motor - Introduction
See section General Specifications
• Use a screened/armoured motor cable to comply with EMC emission specifications (or install the cable
in metal conduit).
• Keep the motor cable as short as possible to reduce the noise level and leakage currents.
• Connect the motor cable screen/armour to both the decoupling plate of the frequency converter and to
the metal of the motor. (Same applies to both ends of metal conduit if used instead of screen.)
• Make the screen connections with the largest possible surface area (cable clamp or by using an EMC
cable gland). This is done by using the supplied installation devices in the frequency converter.
• Avoid terminating the screen by twisting the ends (pigtails), as this will spoil high frequency screening
effects.
• If it is necessary to break the continuity of the screen to install a motor isolator or motor relay, the
continuity must be maintained with the lowest possible HF impedance.

Cable length and cross-section

The frequency converter has been tested with a given length of cable and a given cross-section of that cable. If
the cross-section is increased, the cable capacitance - and thus the leakage current - may increase, and the cable
length must be reduced correspondingly.

Switching frequency

When frequency converters are used together with sine wave filters to reduce the acoustic noise from a motor,
the switching frequency must be set according to the sine wave filter instruction in par. 14-01
quency.
Precautions while using Aluminium conductors
Aluminium conductors are not recommended for cable cross sections below 35 mm². Terminals can accept
aluminium conductors but the conductor surface has to be clean and the oxidation must be removed and sealed
by neutral acid free Vaseline grease before the conductor is connected.
Furthermore, the terminal screw must be retightened after two days due to the softness of the aluminium. It is
crucial to ensure the connection makes a gas tight joint, otherwise the aluminium surface will oxidize again.
All types of three-phase asynchronous standard motors can be connected to the frequency converter. Normally,
small motors are star-connected (230/400 V, D/Y). Large motors are delta-connected (400/690 V, D/Y). Refer to
the motor name plate for correct connection mode and voltage.
Figure 4. 22: Terminals for motor connection
4-18
for correct dimensioning of motor cable cross-section and length.
Switching Fre-
BAS-SVX19C-EN