INGVAR primary current injection test system

• Check miniature circuit breaker F1.

• Overheating may have triggered the thermal protection.

• The thermal protection resets itself automatically after INGVAR cools down. 

• Interupted circuit. 

• Check the connections to the object being tested. If a breaker is being tested, check to see that it is closed.
• Check the connection between Control Unit and Current Unit.
• Check the connectors on the interconnection cable.

• The fuse F2 / F3 has blown

• No Mains. Check that the mains cable is plugged in properly and that mains voltage is present.

• Stop condition is set to INT and F1 is off. Close F1

• Stop condition is set to INT and the output circuit is open.

Change stop condition or close output circuit.

Stop condition is set to INT and the output current is just a few percentage of the measurement range of the ammeter. Increase the current, decrease INT-level or use range or output with lower current rating.

Note: Connecting Current Unit in series will decrease the measurement ranges.

Zero offset need to be calibrated.

INGVAR is set for DC-Measurement while AC is generated or vice versa. (Fault will be approx. 10%). Select proper setting for DC-Measurement (submenu system). 

The test object has higher impedance than expected. Increase the voltage applied from INGVAR by connect the Current Unit in series.

The instrument is not activated. Activate the instrument in the "V/A-METER" menu option if its indicator lamp is not lit.

The stop condition is met but “AUTO” is not activated. Press “RESET”Rif you want the generation time displayed.
 

The measurement time was too short, the HOLD function cannot present any frozen readings or there was not enough time for a range to be selected automatically. Increase the measurement time or select a fixed range.

The magnitudes of the input signals are too great for the fixed preset range. Or the "AUTO" range does not have time to function properly for high-speed cycles. (”OF” =Overflow). Carry out a new measurement or select a fixed range.

Because the measurement current is 0, no ratio can be calculated. Generate current.

Ammeter cannot present measured values for the generated current because: Current Unit unknown because it is uncalibrated. Calibrate the Current Unit.
 

Increase INT-level or use range or output with higher current rating.

Proper primary injection testing of low voltage circuit breakers (LVCB) will confirm that they trip at the correct times and can properly isolate a fault. A coordination study is performed, and parameters are set to minimise the amount of interruption to other equipment. The characteristics of the circuit breakers are presented in the form of trip curves, and each circuit breaker will have a unique trip curve published by the manufacturer. The trip curves will have bands, or limits, that show how long it takes for the circuit breaker to trip when a certain amount of current is applied; the current is typically presented in multiples of the rated current. As long as the circuit breaker trips within the specified band, it operates correctly. You may perform up to four primary injection test types to verify that the LVCB is working correctly: a long time test, short time test, instantaneous test, and earth/ground fault test. The long, short, and ground fault tests all have a delay component. In contrast, the instantaneous test trips the circuit breaker immediately.

The long time test is a test of the overload function and requires two settings. The first setting is the pickup, which determines the load current level that is tolerable before an overload condition occurs. The second setting is the time delay that determines how long the overload condition is acceptable. Systems are generally designed to handle overload conditions for a short time. Still, damage will occur if the overload persists for too long. You typically perform a long time test at 3 times the rated current.

The short time test is also an overload test with a pickup time like the long time test but has a shorter duration with a higher current. Typical currents are at 6 times the rated current. A short time setting on the breaker is used to allow high current loads for a short duration, for example, a motor starting.

The instantaneous trip conditions test the breaker under fault conditions. Therefore, there is no intentional time delay built in, and the breaker should trip within milliseconds. If the circuit breaker fails to trip and clear the fault, this may result in damage to equipment or personnel. Additionally, an upstream breaker may need to clear the fault, resulting in other electrical system components unrelated to the fault being shut down. An instantaneous trip is typically tested using 8 to 12 times the rated current.

An earth/ground fault trip in the circuit breaker occurs when higher-than-normal currents flow through the ground path. Like the long time and short time functions, the ground fault has both a pickup current and a delay time. Both can be adjusted to fit the coordination study. There is typically a maximum delay that is permitted from ground fault conditions.

Each test is performed separately for each phase. As long as the trip time falls between bands on the time-current curves, the circuit breaker is considered to be in working condition.

Note: the ground fault sensor must be disabled to test long, short, and instantaneous trips.