The Contact Timer measures the exact circuit breaker opening or closing time. Timing starts from the moment that the DC trip or closing contacts ‘make, to the instant there is either a loss of current in the protection CT secondary for an opening time, or the appearance of current in the protection CT secondary for a closing time. The Contact Timer is presented in a tough ABS pocket sized case. It is powered by a PP3 Alkaline battery and provides a clear LCD read-out of time in milliseconds. Crocodile clip leads are provided with the instrument to make the necessary connections to the DC circuit and a clip-on CT is provided for the AC connection. The instrument can be switched on/off by the slide switch on the side of the case. As a precaution against unnecessary battery drain the timer incorporates an auto-switch off facility, which functions 30 minutes after the last reading. The front display has a yellow switch for the change-over from opening to closing times and a soft touch reset switch to allow the previous time read-out to be reset to zero.

• MEASURES THE EXACT OPENING and CLOSING TIME of CIRCUIT BREAKER MAIN CONTACTS
• USE ON CIRCUIT BREAKERS in SERVICE POSITION
• IDENTIFIES the SLOW OPERATING MECHANISM
• TAKES SECONDS to CONNECT
• CLEAR READ-OUT DISPLAY in MILLISECONDS
• POCKET SIZED INSTRUMENT

The Bowden CONTACT TIMER has been developed from the extremely popular Contact Opening Timer. It is a compact and easy to use instrument, which enables distribution engineers to identify the slow operating mechanism before the circuit breaker is called on to operate under fault conditions.

Operation
1. Connect crocodile clips across circuit breaker ‘closing’ or ‘trip’ coil, depending on time function required. The trigger voltage can be between 30 and 240V a.c. or d.c.

2. Clip the current transformer round any one of the protection CT secondary wires. A current minimum of 10mA is required in the protection CT secondary.

3.Switch on the instrument. Check the opening/closing selector switch is in the correct position for time function required and LCD is at zero.

4.Trip or Close the circuit breaker using the dc supply and read the time in milliseconds on the LCD when the circuit breaker has completed its operation.

5. If ‘LOW BAT’ appears in the top left hand corner of the LCD, replace internal PP3 battery.








Specification
Trigger voltage: 30V to 240V ac or dc
Battery::- 1 x PP3 9V
Auto-switch of 30 minutes after last reading.
Specification subject to change without notice
Dimensions: 80 x 150 x 30 mm (excluding the leads)
Weight: 300 grms (excluding leads)
Current range: Protection CT ac current range 10mA-5A

:- :- :- Accuracy cannot be guaranteed with current values below 10mA.

:- :- On a 400/5 CT this represents 0.8 amps in the primary circuit.
Time range: 0 -- 999 milliseconds