During the use of power test equipment, errors may occur due to operational mistakes. Below, experts from HV HIPOT provide an example to introduce the handling of common errors for a product – the switch mechanical characteristic tester.
The instrument indicates “Output short circuit or excessive load. Please shut down and check the control wiring.”
(1) The incorrect wiring was controlled, resulting in a short circuit in the instrument’s output, triggering the short circuit protection function. As a result, the “closing and opening control power supply” of the instrument had no output.
Solution: After powering off, refer to the above item 1 and recheck the wiring.
(2) The on-site coil is overloaded, causing the instrument to fail to operate normally.
Solution: ① For the electromagnetic switch, the driving current required by the closing coil is very high (up to 100A or several hundred amperes), while the maximum load capacity of the instrument’s operating power supply is only 20A. This results in an excessive load, preventing the instrument from functioning properly.
At the site, the closing control line is usually connected to the coil of the closing contactor at the preceding stage of the closing coil. The switch contactor is controlled by an instrument to close, and the contactor then drives the closing coil of the switch to make it operate. Alternatively, the switch closing can be operated using the “external triggering” method.
② For the switches with hydraulic and spring mechanisms, since the instrument defaults to “excessive load” when the output current exceeds 6A. Please check or measure the resistance value of the closing coil with a multimeter to confirm that the current of the closing coil is relatively large. Then, carefully inspect the wiring to ensure that there is no short circuit in the closing output. If so, disable the short circuit protection function of the instrument and conduct the test. (Note: After disabling the short circuit protection function of the instrument, the “closing and opening control power supply” output will no longer have protection function. If the control power supply output is indeed in a short circuit state at this time, it may cause damage to the control power supply of the instrument! Please operate with caution.)
The specific method is as follows: Power off → Press and hold the key without releasing it → Turn on the device, until the “Release Key” screen prompt appears → Release the key, and the short-circuit protection function will be cancelled.
Note: Once the instrument is restarted or reset, the short circuit protection function will be activated again.
Post time: May-11-2026