Eaton Industrial Switchgear - General Information

2010

CA08103002Z-EN

www.eaton.com

22/10

Switchgear for North America

discrete devices. They are rated in HP

and – if they are equipped with

auxiliary contacts – they contain duty

type information for use as controlgear

(

pilot duties). The devices have fixed or

adjustable magnetic or electronic

short-circuit releases

and adjustable

bimetallic or electronic releases for

motor overload protection. They can

be used for switching motor circuits,

and their auxiliary contacts for

switching control circuits. In the PKE

system, the modular plug-in trip blocks

can be exchanged depending on the

size of the connected motor. The

electronic releases have a wide

adjustment range. The PKE system

also allows motor starters to be

networked through the NA-approved

SmartWire-Darwin system. PKZ and

PKE must be used only for protecting

and switching motors in North

America and not, like in IEC/EN, for

other types of load. The circuit

breakers can optionally equipped with

undervoltage or shunt releases.

Although PKZ motor-protective circuit

breakers have an inherent short-

circuit withstand capability at small

currents, they must, according to

North American standards, always be

operated with an upstream short-

circuit protection device (exceptions:

UL 508 Types E and F). For most

devices the specifies short-circuit

protection can also be used to protect

a group of motor-protective circuit

breakers. In North America this

characteristic is referred to as group

protection. When forming groups and

choosing cables, special rules of the

codes and standards must be

observed. If the motor starters’ cable

dimensions vary significantly, the

groups are difficult to coordinate and

some devices can be used only with

separate protective devices in this

case. Motor-protective circuit

breakers with upstream protection

can also be used without limitation in

delta and ungrounded star networks.

Motor starters without additional

short-circuit protection, UL 508

type E starters

According to a supplement to UL 508,

motor starters can be tested as “type E

combination motor controllers”

for

which an additional short-circuit

protection is not required (self-

protected combination motor

controller). This starter type is also

CSA-recognized for Canada. Type E

starters must be used only in solidly

grounded star networks, for example

at slash voltage 480Y/277 V. They must

be used only for switching and

protecting motors and for no other

load types.

For the protection of motors and

frequency inverters, the frequency

inverters must be tested and approved

by their manufacturers together with

these Type E starters (at the time of

print, this possibility is being planned

and not yet officially included in the

standards).

All components for a complete motor

starter, including full short-circuit

protection, are contained in a single

device. This reduces the required

space and eliminates the wiring

between the components. These

devices are used in motor control

centres (MCC), in controllers and

enclosed discrete equipment. Up to

the specified switching capacity,

these devices do not need additional

short-circuit protection.

In the PKZ2 system, these devices are

available with type designation

PKZ2/ZM-.../S-SP. These devices

feature large clearances and

creepage distances. In individual

motor outgoers they can perform the

BCPD function without additional

upstream protection. They can be

tripped by optional undervoltage or

shunt releases and remotely switched

on and off with optional remote opera-

tors. The PKZ2 system also includes a

trip block version that actuates a relay

output on overload instead of tripping

the circuit-breaker through the

breaker mechanism

This version

allows separate signaling of overloads

and short-circuits. On overload, the

circuit-breaker does not have to be

closed again after the fault is rectified.

These breakers are used when the

overload is self-canceling or can be

easily remedied by operating

personnel. This avoids the need to call

in an electrician.

UL 508 manual Type E starters

In addition, the “type E combination

motor controllers” comprise the

“

manual self-protected starters”,

which, if no upstream short-circuit

protective devices are used, require

larger clearances and creepage

distances, for example according to

UL 489 or CSA-C 22.2 No. 5-09. These

devices are suitable only for manual

switching of motors. They must be

used only in solidly grounded star

networks, for example at slash voltage

480

Y/277 V. In individual motor

outgoers they can perform the BCPD

function without additional upstream

protection. They must be used only for

switching and protecting motors and

for no other load types.

Manual self-protected combination

motor controllers are implemented as

a modular system with a PKZM0,

PKZM4 or PKE with a special

additional incoming terminal

BK25/3-PKZ0-E or BK50/3-PKZ4-E. For

use in Canada these devices must, in

addition, be lockable, i.e. the starters

must be fitted with operating handle

AK-PKZ0. It is permissible to connect

several PKZM at their input side with

three-phase commoning links, for

example B3…-PKZ0, and to connect

this group through only a single

incoming terminal BK….

UL 508 Type F remote-switchable

starters

By combining a “manual type E

starter” with a contactor, a “type F

combination motor controller” can be

constructed. These starters also do

not need additional short-circuit

protection. Type F starters can be

combined and used as shown

on page 8/xx. These combinations can

also be used exclusively in solidly

grounded star networks, for example

at slash voltage 480Y/277 V. They must

be used only to switch motors and no

other types of load. Type F starters are

accepted in Canada, although they are

not yet described in the standards

there.

Here, too, three-phase commoning

links with a single incoming terminal

can be used. Alternatively, the devices

can be mounted on busbar adapters

and busbar systems. The adapters and

busbar systems SASY 60i are also

approved for use in North America.

The Eaton devices offer this very

effective “two-component starter”

with up to 52 A. Up to the specified

switching capacity, these starters do

not need additional short-circuit

protection.

Motor starters for higher-rated

motors

At their basic equipment level, circuit

breakers are not suitable for motor

protection in North America. Like the

conventional IEC/EN-standard circuit

breakers, these breakers lack a motor

protection characteristic for overload

releases that meets the requirements

of current North American codes and

standards. Later in this section, a new

circuit-breaker as motor-protective

circuit-breaker NZM…-ME…-NAwill

be introduced, with a motor protection

characteristic that comforms to

UL 508.

In North America, motor starters for

higher-rated motors (for Eaton devices

> 52 A) are assembled from three

components: A circuit-breaker, a

contactor and an additional overload

relay. The circuit breakers used have

•

with fixed overload releases

(

NZM…-AF…-NA)

•

or with adjustable overload

releases (NZM…-A…-NA)

•

or without overload release

(

NZM..-S…-NA).

The overload relays optionally feature

thermal bimetallic or electronic trip

blocks. The configurable tripping

behavior of electronic overload relays

can be optimized for the motors’

startup behavior under adverse load,

for example for heavy starting duty.

Motor-protectivecircuitbreakers

NZM…-ME…-NA

These novel devices are fully-featured

circuit breakers in North America

(

molded-case circuit breakers to

UL 489 and CSA-C22.2 No. 5-09) and, in

addition, like overload relays contain

an overload release calibration

(

to UL 508 and CSA-C22.2 No. 14-05).

They are used mainly in controllers

and motor control centers (MCC). They

are short-circuit rated in kA and – if

they are equipped with auxiliary

contacts – contain duty type informa-

tion (pilot duties). These circuit

breakers can optionally be equipped

with and tripped by shunt or under-

voltage releases or be switched on

and off with remote operators.

These devices feature adjustable

electronic short-circuit releases and

adjustable electronic wide-range

releases for motor overload

protection

The adjustable tripping

class allows the devices to be adapted

to the starting characteristics of

various different motors and load

types. They can be used as separate,

manual breakers, for protecting and

switching motor circuits, and their

auxiliary contacts for switching

control circuits.

In combination with a downstream

contactor, they are classified as a

“

Type C combination motor starter”, in

which the contactor, acting as motor

controller, switches and regulates the

motor current with a high, reliable

operating frequency and the NZM

provides protection. For these Type C

combination motor starters the HP

ratings indicated on the contactors

then apply. These combinations then

form “two-component motor starters”,

which require less space and fewer

components and engineering

resources, and have lower thermal

losses than three-component motor

starters. This is specially advanta-

geous for the compact withdrawable

MCCs.

Motor-protective circuit breakers

NZM…-ME…-NA can be used with or

without contactor in motor circuits up

to the stated switching capacity

without additional short-circuit

protection. With just three models,

they cover a current range from 45 to

200

A. The circuit breakers are “100 %

rated”, meaning that their entire

current range can be utilized. Their

setting ranges overlap with the two-

component motor starters up to 52 A

that are formedwith the Type E or Type

F versions of circuit breakers PKZM0,

PKZM4 or PKE. Covering currents up to

200

A, the two-component motor

starters can now be used to cost-

effectively protect and switch more

than 95 percent of all motors.

Circuit-breakers

without overload protection,

NZM..-S(E)..-CNA

In North America, these devices are

circuit breakers (instantaneous-trip

only molded-case circuit breakers

according to UL 489 and CSA-C 22.2

No. 5-09) and are used mainly in motor

control centres (MCC), controllers and

enclosed discrete equipment. They

are rated in amperes and – if they are

equipped with auxiliary contacts –

contain duty type information (pilot

duties).

The devices have adjustable magnetic

or electronic short-circuit releases, no

overload releases and can be used for

switching motor circuits, and their

auxiliary contacts for switching

control circuits. They also provide

short-circuit protection in motor

circuits. They can optionally be tripped

by shunt or undervoltage releases or

be switched on and off with remote

operators.

Circuit-breakers NZM..-S(E)..-CNA are

UL-approved as Recognized Compo-

nents. They are not used as discrete

devices; they are always combined to

a “combination motor starter” with a

downstream contactor and overload

relay, in which the contactor performs

operational switching and regulation

of the motor current, the overload

relay acts as overload protective

device and the circuit-breaker acting

as short-circuit protection device. This

combination has the added benefit of

allowing a separate tripped indication

on overload through the overload

relay’s auxiliary contacts or on short-

Notes

Observe previous paragraph

Motor starter construction Type E

ZMR-…-PKZ2, overload is signaled only; the circuit-breaker does not trip

The overload releases are, in addition, calibrated like overload relays in

compliance with UL 508 and CSA-C 22.2 No. 14-05