Electronic Motor Overload Protection - Allen-Bradley PowerFlex 70 Installation Instructions Manual

Adjustable frequency ac drive

Quick start manual

Reference manual (300 pages)

User manual (132 pages)

Table of Contents

Unshielded

Thermoplastic High Heat-resistant Nylon-coated (THHN), Thermoplastic Heat and Water-resistant Nylon-coated (THWN), or similar wire is

acceptable for drive installation in dry environments as long as adequate free air space and/or conduit fill rate limits are provided. The wire must

have a minimum insulation thickness of 15 mils (0.4 mm/0.015 in.) and cannot have large variations in insulation concentricity.

IMPORTANT

Do not use THHN or similarly coated wire in wet areas.

Shielded/Armored Cable

Shielded cable contains the general benefits of multi-conductor cable with the added benefit of a copper braided shield that can contain much of the

noise that is generated by a typical AC Drive. Use shielded cable for installations with sensitive equipment such as weigh scales, capacitive proximity

switches, and other devices that can be affected by electrical noise in the distribution system. Applications with large numbers of drives in a similar

location, imposed EMC regulations, or a high degree of communications/networking are also good candidates for shielded cable.

Shielded cable can also help reduce shaft voltage and induced bearing currents for some applications. In addition, the increased impedance of

shielded cable can help extend the distance that the motor can be from the drive without the addition of motor protective devices, such as

terminator networks. See Reflected Wave in Wiring and Grounding Guidelines for PWM AC Drives, publication DRIVES-IN001.

Consider the general specifications of the environment of the installation, including temperature, flexibility, moisture characteristics, and chemical

resistance. In addition, a braided shield can be included and be specified by the cable manufacturer as having coverage of at least 75%. An additional

foil shield can greatly improve noise containment.

A good example of recommended cable is Belden 295xx (xx determines gauge). This cable has four Cross-linked Polyethylene (XLPE) insulated

conductors with a 100% coverage foil and an 85% coverage copper braided shield (with drain wire) surrounded by a Polyvinyl Chloride (PVC)

jacket.

Other types of shielded cable are available, but the use of these types can limit the allowable cable length. For example, some of the newer cables

bundle four conductors of THHN wire and wrap them tightly with a foil shield. This type of construction can greatly increase the cable charging

current that is required and reduce the overall drive performance. Unless specified in the individual distance tables as tested with the drive, these

cables are not recommended and their performance against the lead length limits is not known.

Recommended Shielded Wire

Location

Rating/Type

Tray rated 600V, 90 °C

Standard (option

(194 °F) RHH/RHW-2

Anixter OLF-7xxxxx or

equivalent

Tray rated 600V, 90 °C

Class I and II;

(194 °F) RHH/RHW-2

Division I and II

Anixter 7V-7xxxx-3G or

equivalent

ATTENTION: To avoid a possible shock hazard that is caused by induced voltages, unused wires in the conduit must be grounded at both

ends. Also, if a drive sharing a conduit is being serviced or installed, disable all drives that are using that conduit. Disabling all drives helps

minimize the possible shock hazard from cross coupled motor leads.

Motor Cable Lengths

Typically, motor lead lengths less than 30 m (approximately 100 ft) are acceptable. However, if your application requires longer lengths, refer to

Wiring and Grounding Guidelines for Pulse Width Modulated (PWM) AC Drives, publication DRIVES-IN001, for details.