angrymonkey
Member
So, I have gotten on a random tangent and decided to find out all that I could about MOC switches and their function in Vac-CB's today.
Most of the information I find is very similar and I need a little help clearing up what exactly it is doing. Here is the type of info I am typically finding:
"A mechanism-operated cell (MOC) switch is typically located in a switchgear cell and is operated by a circuit breaker MOC operator mechanism. A typical example may be found in U.S. Pat. No. 4,176,262. The MOC switch is employed to provide extra or redundant contacts for circuit breaker status and status control.
It is well known that modern technology circuit breaker mechanisms operate with different force, travel, and velocities than older technology breakers. When applying modern technology circuit breaker elements, as retrofit or replacement circuit breakers, for the older technology circuit breakers, worn MOC assemblies may possibly create problems.
Older switchgear MOC assemblies were designed for the circuit breaker technology of the time. Older technology circuit breakers employed relatively massive mechanisms, with relatively high forces and inertias. The resultant travel times and velocities were fairly slow such that, for example, the MOC switch may close in approximately 100 ms, measured from the time the circuit breaker begins to close.
The MOC assembly is typically the only component outside the circuit breaker that affects the dynamics of the circuit breaker. The loading and dynamic characteristics of the MOC assembly are highly variable, as the existing MOC assembly typically may have been in service for some time, with mechanical wear and degradation. "
Okay, the basic idea I get is that its just an extra set of contacts, but it seems to be so much more. I am mainly getting confused when it describes problems MOC's are having with new tech's. Several places describe a "bounce of X seconds" during operation and similar. This sounds important to understand
What I envision is a locking mechanism for the CB essentially, and possibly the "bounce" is the twang + associated noises when a breaker trips? This doesnt seem completely right to me though. It also seems like it has a bit of isolation function for testing as well...
Lots of me scattering around, any help with an organized thought?
Thanks in advance.
Most of the information I find is very similar and I need a little help clearing up what exactly it is doing. Here is the type of info I am typically finding:
"A mechanism-operated cell (MOC) switch is typically located in a switchgear cell and is operated by a circuit breaker MOC operator mechanism. A typical example may be found in U.S. Pat. No. 4,176,262. The MOC switch is employed to provide extra or redundant contacts for circuit breaker status and status control.
It is well known that modern technology circuit breaker mechanisms operate with different force, travel, and velocities than older technology breakers. When applying modern technology circuit breaker elements, as retrofit or replacement circuit breakers, for the older technology circuit breakers, worn MOC assemblies may possibly create problems.
Older switchgear MOC assemblies were designed for the circuit breaker technology of the time. Older technology circuit breakers employed relatively massive mechanisms, with relatively high forces and inertias. The resultant travel times and velocities were fairly slow such that, for example, the MOC switch may close in approximately 100 ms, measured from the time the circuit breaker begins to close.
The MOC assembly is typically the only component outside the circuit breaker that affects the dynamics of the circuit breaker. The loading and dynamic characteristics of the MOC assembly are highly variable, as the existing MOC assembly typically may have been in service for some time, with mechanical wear and degradation. "
Okay, the basic idea I get is that its just an extra set of contacts, but it seems to be so much more. I am mainly getting confused when it describes problems MOC's are having with new tech's. Several places describe a "bounce of X seconds" during operation and similar. This sounds important to understand
What I envision is a locking mechanism for the CB essentially, and possibly the "bounce" is the twang + associated noises when a breaker trips? This doesnt seem completely right to me though. It also seems like it has a bit of isolation function for testing as well...
Lots of me scattering around, any help with an organized thought?
Thanks in advance.
