Safety Isolation System

12-3

ElectroGuard

Overview

Principle of Operation

Optional Features

2IC

1IC

GC

Incoming

3 Phase

Power

H2

H1

X2

X1

Control Power

Disconnecting

Means/Branch

Circuit Protection ➊

Trans.

Grd

Voltage

Decay

Relays

(VDR)

To Motor

Controllers

Power Circuit

To Loads

After using the normal stopping

method of the machine or process,

the machine operator turns a

Remote Lockout Station handle

from the “On” to “Off ” position.

The station signals the isolation

contactors (1IC and 2IC) to drop

out and isolate the supply voltage

from the loads (see Control

Circuit).

When system residual voltage

decays to pre-determined levels,

the grounding contactor (GC) is

energized, connecting the load to

ground (see Power Circuit). The

grounding contactor (GC) is

electrically and mechanically

interlocked with the isolation

contactors (1IC and 2IC).

The “System Isolated” Light will

now illuminate on the Remote

Lockout Station to indicate the

system is isolated. The machine

operator then Locks-Out and

Tags-Out the station in the “Off ”

position.

Control Circuit

Remote Lockout Station

Off

On

Mechanically

Interlocked

1IC, 2IC, &

GC are

mechanically

and electrically

interlocked

System Isolated (*)

(*) = “On” when the Remote

Lockout Station switch is “Off”

GC

GC

2IC

1IC

VDR

2IC

1IC

GC

2

IC

1

IC

GC

➊ Available factory installed within the ElectroGuard as an option.

• Four (4) or ten (10) port Expansion Modules to permit additional Remote

Lockout Stations to be used (see page 12-16 for details).

• Pneumatic Isolation Module to isolate pneumatic energy (see page 12-15 for

details).

• Status communication to a remote PLC (see page 12-17 for details).

• Fusible disconnect switch (Bulletin 2032) or thermal-magnetic circuit breaker

(Bulletin 2033) to provide branch circuit protection.

Optional Pneumatic Isolation Module