Designed to test low-voltage dc circuit breakers with dc current, the Megger CB-360-DC/CB-120-DC DC Circuit Breaker Test Sets provide the capability of calibrating and functionally testing the time-delay characteristics of the electromechanical or thermal-magnetic trip devices on dc circuit breakers.
Megger CB-360-DC/CB-120-DC DC Features and Benefits:
Digital timer: A specially designed, solid-state digital timer is incorporated to measure the elapsed time of the test in either seconds or cycles. It features extensive shielding and noise-suppression circuitry to ensure accurate and reliable operation under the most demanding field conditions. Accuracy of the timer, which incorporates a crystal-controlled oscillator, is independent of the power-line frequency.
Timer control circuit: This circuit automatically starts the timer when the output is energized and automatically stops the timer and de-energizes the output when the device under test is operating. This circuit accommodates the following test conditions by simple switch selection of the appropriate mode.
Current actuated: This mode is used to test a device that has no auxiliary contacts to monitor, such as a single-pole circuit breaker. The timer stops when the output current is interrupted.
Normally closed: This mode is used to test a device with normally closed contacts. The timer stops and the output is de-energized when thecontacts open.
Normally open: This mode is used to test a device with normally opencontacts. The timer stops and the output is de-energized when the contacts close.
Output connections: To permit direct connection of many types of drawout-style circuit breakers to the test set, Model CB-360-DC is equipped with a stab adapter board and Model CBS-1 and Model CBS-2 stab sets. Please refer to the catalog entry for the Megger Circuit Breaker Stab Sets to determine the uses of the included stab sets. If the included stab sets will not test all breakers, refer to the Model CBS-3 optional stab set list.
Overload protection: The test set is provided with circuit breakers, overload relays and fuses to protect it from extreme or prolonged overloads. Additionally, the output section is forced-air cooled and is equipped with a temperature-sensitive interlock switch that de-energizes the unit in the event of abnormal heating of the rectifiers.
Enclosures: For safety and mobility, the test set is in a rugged, two-piece enclosure, each section having a low center of gravity, large locking casters and eye hooks for lifting.