What Problems will the Relay Encounter in Practical Applications?

May. 09, 2020

As a Power Relay Manufacturer today, I will mainly share with you what problems will relays encounter in practical applications?

1. Coil voltage

It is best to design the voltage of the coil according to the rated voltage. If not, please refer to the temperature rise curve. The use of any coil voltage less than the rated operating voltage will affect the operation of the relay.

Note that the working voltage of the coil refers to the voltage applied between the terminals of the coil. Especially when the amplifier circuit is used to excite the coil, the voltage between the two terminals of the coil must be ensured.

NB901 Relay

NB901 Relay

Conversely, when the maximum rated working voltage is exceeded, the performance of the product will also be affected. Excessively high working voltage will cause the temperature of the coil to rise too high, especially at high temperatures, which will damage the insulating material and affect the operation of the relay.

For magnetic holding relays, the pulse width of the excitation (or reset) should not be less than 3 times of the pull-in (or reset) time, otherwise the product will be in the neutral state.

When a solid-state device is used to excite the coil, its device withstand voltage is at least 80V and the leakage current must be small enough to ensure the release of the relay.

2. Transient suppression

When the relay coil is de-energized, an inverse peak voltage that is more than 30 times higher than the rated working voltage of the coil can be generated on the coil, which is extremely harmful to the electronic circuit.

Parallel transient suppression (also called peak clipping) diodes or resistors are usually used to suppress, so that the reverse peak voltage does not exceed 50V, but the parallel diode will extend the release time of the relay by 3 to 5 times. When the release time requirement is high, a suitable one can be connected in series at the diode end.

Resistance excitation power supply: at 110% rated current, the power supply adjustment rate is ≤ 10% (or the coil impedance of the output impedance <5%), and the ripple voltage of the DC power supply should be <5%.

The AC waveform is a sine wave, the form factor should be between 0.95 and 1.25, the waveform distortion should be within ± 10%, and the frequency change should be within ± 1 Hz or ± 1% of the specified frequency (whichever is greater).

Its output power is not less than the power consumption of the coil.

Our company also has NB901 Relay for sale, please contact us.


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