The LD-3 type rotor one point grounding relay (hereinafter referred to as the relay) is used to monitor the insulation of the excitation circuit of large generator rotors to ground. When a grounding fault occurs in the rotor of the generator or when the insulation drops to a certain value, the relay immediately acts, issuing a fault signal or directly tripping.

structure
The relay adopts an embedded rear wiring (JK-31K) structure.

Technical requirements for LD-3 rotor one point grounding relay

1. AC rated value 50Hz, 100V or 220V
2 action resistors
2.1 Setting range
0.5，1，2，5，10，15，20kΩ.
2.2 Setting error
The average of ten measurements is compared with the set value, and the error does not exceed ± 10%.
2.3 Return coefficient
Not greater than 2.
When the action time is 0.8 times the action resistance, it should not exceed 0.2 seconds.
4. Influence of capacitance
After connecting a parallel capacitor of 2 μ F to the subject's resistance, the change in action resistance compared to when there is no capacitor does not exceed ± 10%.
5. Impact of AC power supply
5.1 Voltage Influence: At 90% to 110% of the rated voltage, the change in operating resistance should not exceed 10% compared to the rated voltage.
5.2 Frequency Influence: The change in operating resistance between 47Hz and 53Hz should not exceed ± 10% compared to 50Hz.
6 Temperature effects
When the ambient temperature changes within the range of -5 ℃ to+45 ℃, the average of ten measurements of the relay's operating value shall not differ by more than 10% compared to the average of ten measurements of the operating value under the reference conditions (20 ℃± 2 ℃).
7-contact disconnect capacity
When the voltage does not exceed 220V and the current does not exceed 0.2A, the breaking capacity of the relay contacts is:
a. In a DC inductive load circuit (τ=5ms ± 0.75ms), it is 20W;
b. In the AC circuit (cos φ=0.4), it is 30VA.
8 Power consumption
The AC power supply consumes no more than 18VA at 50Hz and 220V.
The weight of the relay should not exceed 10kg.

Ordering Instructions
When placing an order, please specify:
a. Product model and specifications, shell structure form;
b. Name, code, and quantity of required spare parts;
c. Order quantity and delivery address.

３. Installation size:

LD-3 type rotor one point grounding relay