1. KELMAN CIRCUIT BREAKER ANALYZER
EUS 220

2. The Kelman Circuit Breaker Analyzer is used to test the timing/condition of the operating mechanism of the power circuit breaker.
The Kelman monitors trip/close coil current, CT secondary current, and also DC voltage.
The results of this data can tell you the condition of the breakers operating mechanism and lubrication of the breaker. It will also tell you the operation time of the main contacts (“a”,”b”).

3. HOW TO CONNECT THE KELMAN DEVICE
When using the Kelman device you will use four separate leads.
You will connect two leads to the DC voltage supply of the circuit breaker (positive and negative).
Then you connect an AC clamp-on lead to one phase of the CT secondary (main contact operating time).
Last you will connect a DC clamp-on to the trip/close circuit of the breaker.
Figure of lead connections on the following slide.

5. Main contact time
“a” contact opens
DC supply
Breaker comes off latch, operating mechanism starts to move
Trip coil solenoid hits latch

6. WHAT CAN CAUSE A SLOW BREAKER MECHANISM?
Poor lubrication of the breaker operating mechanism.
Trip/Close Coil failures.
Battery/Battery charger problems.
Bad aux switches.
Loose connections in the control circuit.

7. Faulty Lubrication in Mechanism
First shot, breaker slow to come off latch
Second shot
Shot taken after second operator overhaul

8. Comparing 3 Breakers Three breakers of same type, one with slowing
trip latch.

9. Battery Problem
Drop in battery voltage
during shot.

10. Battery Problem Failed batteries, battery charger doing the work.
Voltage trace.
Current trace.

11. Loose Connections
Loose connections
in control circuit.