HJLF Series Inverse Time Current Relays This series of relays is used as a starting element for motors, transformers, transmission line overload and short circuit protection.
HJLF series inverse time current relay
HJLF inverse time current relay
1. Features and Uses This series of relays is used as a starting element for motors, transformers, transmission line overload and short circuit protection. The relay has both anti-time limit and quick-break protection functions. The action time limit decreases with the increase of current I. When the current I is greater than N times (speed override ratio) Idzf (set inverse time overcurrent protection start current), the relay acts immediately. .
The operating current range of this series of relays is 0.1A~9.9A. When it exceeds 9.9A, it may be saturated, the measurement accuracy will be reduced, but the relay will not be damaged. The relay can allow 100A/1 second or 50A/10 second overload. If the operating current is greater than 9.9A, it is recommended to access this relay via CT.
The relay uses a four-digit digital tube to display the measured current. If two or three currents are input, the maximum phase current is displayed, and the maximum phase current is used as the protection target.
The delay action characteristic of the relay is a very inverse time curve:
t is the action delay time, k is the inverse time overcurrent protection coefficient
I is the input measurement current, and Idzf is the starting current of the inverse time overcurrent protection.
The user must set three parameters to use this relay:
1) Starting current Idzf for inverse time overcurrent protection.
2) Quick override N. When the input current is greater than I>Idzf×N, the relay will immediately act and no longer delay.
3) The inverse time overcurrent protection coefficient K, changing K, will make the characteristic curve move up and down, changing the delay working time under the same overload multiple. See Table 1 and the inverse time overcurrent protection characteristic curve for the specific delay time.
2. Product number
3. Technical parameters
(1). Auxiliary power supply: 85~260V AC and DC universal.
(2). Protection current range: 0.1~9.9A, maximum allowable 100A/1 second or 50A/10 second overload.
(3). Input current frequency: 45~65Hz.
(4). Quick override N setting range: 2~99, but be sure to ensure N×Idzf (5). The quick-break action time is less than 0.1 second.
(6). The inverse time error is less than 3%+0.1S.
(7). Contact capacity: 5A can be switched on for a long time, 250VDC can be disconnected Ï„=5ms 50W DC sense load;
Can disconnect 250VAC COSΦ=0.4, 250VA AC load.
4. Precautions
(1). The protection current range of this relay is 0.1~9.9A. When it is greater than 9.9A, the relay may be saturated and the measurement error will increase. If the protection current is greater than 9.9A, it is recommended to access via CT.
(2). When setting the inverse current overcurrent protection starting current, it should be selected according to the principle of avoiding the maximum continuous load current.
(3). If the load is a motor, avoid the starting current when setting the quick override.
5. Wiring diagram
HJLF inverse time current relay wiring diagram
Inverse time overcurrent protection characteristic curve
Action characteristic curve when inverse time and quick action
HJLF series inverse time current relay
HJLF inverse time current relay
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