Handle Operating Devices
Handle operating devices provide indirect electrical or manual operation of the circuit breaker handle.Electrical operators provide complete remote control of a molded case circuit breaker by means of a pushbutton or similar pilot device. When energized from a remote location, the operator mechanism moves the circuit breaker handle to either the ON or OFF position. Shunt trips and undervoltage release mechanisms can only be used to trip the breaker. Electrical operators deliver a positive switching action. In case of a power failure, means are provided for manual operation. They come in a variety of designs and, depending on the circuit breaker type, are mounted in different ways.
The newer designs are front mounted on the breaker cover and fit within the trim line of the circuit breaker. For smaller frame breakers, a solenoid is used. On larger frame sizes, a motor is used to provide the increased operational force required to move the breaker handle.
Front Mounted Electrical Operator (Solenoid Type)
Some designs are side mounted and use an extended arm to move the circuit breaker handle. These older motor driven operators are not usually suitable for generator synchronizing because of the time it takes for operation.
Side Mounted Electrical Operator (Motor Type)
Contemporary electrical operator designs, whether solenoid or motor driven, are capable of performing a closing operation in five cycles or less. This makes them very suitable for generator synchronizing applications.
Handle mechanisms allow for the manual operation of the circuit breaker toggle handle. These mechanical devices allow personnel to open and close the breaker without opening the enclosure in which the breaker is mounted. They come in a variety of designs for different applications and enclosure types.
The flex shaft type handle mechanism is an extra heavy-duty mechanism designed for mounting in flange-type enclosures. An operating handle, flexible shaft and mechanism are required for standard application.
Flex Shaft Handle Mechanism
Handle mechanisms are often designed to indicate the status of the circuit breaker because the breaker itself is often not visible when the handle operates. Some designs allow for protection against tampering, or to tag and lockout during maintenance. The unit shown here will accept up to three padlock shackles.
Safety Handle Mechanism
Rotary handle mechanisms mechanically transfer the rotating operation to the in-line toggle operation of the circuit breaker handle. Depending on their design, they may allow mounting an auxiliary switch on the handle for undervoltage release. Some devices are available with red handles and yellow background labels to meet local codes.
Rotary Handle Mechanisms
Lock and Interlock Devices
Lock and interlock devices are used to deter undesired circuit breaker operation and establish interlocked control systems. They do not interfere with the trip-free operation of the molded case circuit breaker.
The nonlockable handle block secures the breaker handle in either the ON or OFF position to prevent accidental operation.
Nonlockable Handle Block
The padlockable hasp mounts on the circuit breaker cover and will allow multiple padlocks to secure the handle in either the ON or OFF position.
Padlockable Hasp
The cylinder lock internally blocks the breaker trip bar in the tripped position. This prevents the breaker from being switched ON. However, use of a cylinder lock may reduce the interrupting rating of the breaker.
Cylinder Lock
A key interlock is used to externally lock a circuit breaker handle in the OFF position. An extended deadbolt blocks movement of the breaker handle. The key is only removable in the locked position.
Key Interlock
To prevent adjacent breakers from being switched to the ON position, a sliding bar interlock can be used. When the sliding bar handle is moved from one side to the other, a bar extends to alternately block the breaker handle.
Sliding Bar Interlock
Along the same lines, the walking beam interlock provides mechanical interlocking between breakers of the same pole configuration. It mounts on a bracket behind and between the breakers.
Walking Beam Interlock
Miscellaneous Devices
Certain molded case circuit breakers can have their interrupting rating increased to 200,000A symmetrical at up to 600V. The device used for this is called a current limiting attachment. It is bolted to the load end of the circuit breaker so that it will interrupt normal fault current up to 50 or more times the breaker's continuous rating. The limiter will only trip when a very high fault is encountered. As the limiter trips, the breaker is also tripped magnetically, preventing a single-phasing condition.
A spring loaded indicator is on each pole of the limiter to identify the faulted phase. When a current limiter trips, it is an indication of a serious circuit problem that must be corrected before restoring service. To ensure the proper limiter is used with a compatible breaker, they are always of a noninterchangeable design.
Current Limiting Attachment
Another device designed to protect personnel and equipment is the low level earth leakage (ground fault) protector. This device usually trips the circuit breaker through a shunt trip or undervoltage release mechanism when it detects a low level ground fault.
Earth Leakage Protection
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Circuit Breaker
Handle operating devices provide indirect electrical or manual operation of the circuit breaker handle.Electrical operators provide complete remote control of a molded case circuit breaker by means of a pushbutton or similar pilot device. When energized from a remote location, the operator mechanism moves the circuit breaker handle to either the ON or OFF position. Shunt trips and undervoltage release mechanisms can only be used to trip the breaker. Electrical operators deliver a positive switching action. In case of a power failure, means are provided for manual operation. They come in a variety of designs and, depending on the circuit breaker type, are mounted in different ways.
The newer designs are front mounted on the breaker cover and fit within the trim line of the circuit breaker. For smaller frame breakers, a solenoid is used. On larger frame sizes, a motor is used to provide the increased operational force required to move the breaker handle.
Front Mounted Electrical Operator (Solenoid Type)
Some designs are side mounted and use an extended arm to move the circuit breaker handle. These older motor driven operators are not usually suitable for generator synchronizing because of the time it takes for operation.
Side Mounted Electrical Operator (Motor Type)
Contemporary electrical operator designs, whether solenoid or motor driven, are capable of performing a closing operation in five cycles or less. This makes them very suitable for generator synchronizing applications.
Handle mechanisms allow for the manual operation of the circuit breaker toggle handle. These mechanical devices allow personnel to open and close the breaker without opening the enclosure in which the breaker is mounted. They come in a variety of designs for different applications and enclosure types.
The flex shaft type handle mechanism is an extra heavy-duty mechanism designed for mounting in flange-type enclosures. An operating handle, flexible shaft and mechanism are required for standard application.
Flex Shaft Handle Mechanism
Handle mechanisms are often designed to indicate the status of the circuit breaker because the breaker itself is often not visible when the handle operates. Some designs allow for protection against tampering, or to tag and lockout during maintenance. The unit shown here will accept up to three padlock shackles.
Safety Handle Mechanism
Rotary handle mechanisms mechanically transfer the rotating operation to the in-line toggle operation of the circuit breaker handle. Depending on their design, they may allow mounting an auxiliary switch on the handle for undervoltage release. Some devices are available with red handles and yellow background labels to meet local codes.
Rotary Handle Mechanisms
Lock and Interlock Devices
Lock and interlock devices are used to deter undesired circuit breaker operation and establish interlocked control systems. They do not interfere with the trip-free operation of the molded case circuit breaker.
The nonlockable handle block secures the breaker handle in either the ON or OFF position to prevent accidental operation.
Nonlockable Handle Block
The padlockable hasp mounts on the circuit breaker cover and will allow multiple padlocks to secure the handle in either the ON or OFF position.
Padlockable Hasp
The cylinder lock internally blocks the breaker trip bar in the tripped position. This prevents the breaker from being switched ON. However, use of a cylinder lock may reduce the interrupting rating of the breaker.
Cylinder Lock
A key interlock is used to externally lock a circuit breaker handle in the OFF position. An extended deadbolt blocks movement of the breaker handle. The key is only removable in the locked position.
Key Interlock
To prevent adjacent breakers from being switched to the ON position, a sliding bar interlock can be used. When the sliding bar handle is moved from one side to the other, a bar extends to alternately block the breaker handle.
Sliding Bar Interlock
Along the same lines, the walking beam interlock provides mechanical interlocking between breakers of the same pole configuration. It mounts on a bracket behind and between the breakers.
Walking Beam Interlock
Miscellaneous Devices
Certain molded case circuit breakers can have their interrupting rating increased to 200,000A symmetrical at up to 600V. The device used for this is called a current limiting attachment. It is bolted to the load end of the circuit breaker so that it will interrupt normal fault current up to 50 or more times the breaker's continuous rating. The limiter will only trip when a very high fault is encountered. As the limiter trips, the breaker is also tripped magnetically, preventing a single-phasing condition.
A spring loaded indicator is on each pole of the limiter to identify the faulted phase. When a current limiter trips, it is an indication of a serious circuit problem that must be corrected before restoring service. To ensure the proper limiter is used with a compatible breaker, they are always of a noninterchangeable design.
Current Limiting Attachment
Another device designed to protect personnel and equipment is the low level earth leakage (ground fault) protector. This device usually trips the circuit breaker through a shunt trip or undervoltage release mechanism when it detects a low level ground fault.
Earth Leakage Protection
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