Abstract: Switches of telephone grids are tested for delayed action subsequent to, but within a number of milliseconds after, actuating the opening or closing of the switches. Excessive delay indicates approaching failure.

Abstract: Equipment is provided to test an electrical device, e.g. solenoid, or heater that effects an operation, e.g. movement of a valve, heating etc. To perform a test, the equipment actuates the device to cause the operation to commence. When the operation has proceeded to a predetermined extent, or after a predetermined time, whichever occurs first, a signal is produced which causes de-actuation of the device thus stopping the operation. A signal is also produced to indicate whether it was the elapse of the specified time or the operation proceeding to the specified extent that caused de-actuation. The equipment is particularly suited for testing a device forming part of a trip system.

Abstract: Electromagnetic actuator release characteristics are evaluated by sampling at high frequency the voltage waveform resulting when the magnet coil is deenergized. The samples are converted to a digitally coded form and stored in sequence. The stored values are then examined in reverse sequence to identify the first examined sampling interval in which the sample value exceeds a predetermined characteristic release level for the electromagnetic actuator. Finally, the release time is determined by calculating the time after energization corresponding to the sampling interval that has been identified as the release interval.

Abstract: In a relay tester, analog signals to be supplied to a relay under test are processed with digital circuits so that the concerned frequency, phase, voltage and current are set and adjusted with high frequency.

Abstract: Relays and similar devices are tested by applying electric power to the coil to actuate the armature, measuring armature travel and comparing the measured travel to a datum to produce a percentage relationship. Datum values for the armature travel required to actuate each contact are connected by this produced percentage relationship to produce new datum values for each contact. The armature travel at actuation of each contact is measured and compared to the new or connected datum values. Output signals are desired for the actuation of each contact indicative of the relationship between actual actuation travel and the new datum values.