Intermediate relay is a control relay. Generally used for auxiliary purposes, that is, the control circuit requires a larger number of contacts, a larger capacity, through the intermediate relay can increase the number of control circuits or signal amplification. Work, when the coil voltage reaches the specified value, the intermediate relay will be action. This article describes the common intermediate relay troubleshooting.
As the relay structure and the contactor is basically the same, so the contact part of the electromagnetic system and common faults, diagnosis and countermeasures can refer to the relevant part of the contactor. It only needs to be pointed out that the contact of the intermediate relay is apt to produce the virtual connection fault, which often happens during the work of the electrical control. It is not always happen or fixed, so it is difficult to catch and make the fault difficult to judge.
Occasional accidents can cause serious accidents. The reason for this failure is due to the control loop of the contact resistance changes, making the actual voltage across the electromagnetic coil less than 85% of the rated voltage, so that the core can not pull, causing the circuit out of control.
The best way to eliminate the intermediate relay failure is:
(1) try to avoid the use of 12V and below the low voltage as the control voltage, because in this low voltage circuit, the most prone to contact virtual fault.
(2) Control circuit using 24V for control voltage, should be used in parallel contacts, in order to improve its operational reliability.
(3) Control circuit must be low-voltage control to 48V as well.
(4) The control circuit is best to use 110V and above voltage as the rated control voltage, which can effectively prevent the phenomenon of contact virtual connection.