ZHEJIANG HUAYANG ELECTRIC CO., LTD.
Electronic Overcurrent Relay EOCR LT47

Electronic Overcurrent Relay EOCR LT47

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Customers can easily find our Electronic Over Current Relay EOCR LT47 in spin dryers, fans, pumps, mixers and more. Earlier, our relay was deployed for motors; however with evolving electronics advancement tends for individuals to use its advancement to each industrial field with its superior flexibility and accuracy.

Electronic Over Current Relay EOCR LT47

LT47 electronic over current relays have been developed to satisfy machine protection requirements. These relays have definite time characteristics: current threshold and time based function. They are particularly recommended for providing mechanical protection on machines with high resistive torque, high inertia and with strong probability of jamming under steady state conditions. They can be used for motor protection in the case of long starting times or frequent starting. The LR97 D relay also incorporates two fixed time protection functions, one of 0.5 seconds against locked rotor and one of 3 seconds against phase failure. LR97 D and LT47 can be used to provide mechanical shock protection. In this case, setting the 0-Time knob to minimum will ensure tripping in 0.3 seconds.

Applications:

  • LT47 relays are particularly suitable for the following machines:
  • Monitoring function for excessively long starting time on machines with a risk of difficult starting:
  • Machines with high resistive torque, high inertia machines.
  • Monitoring of machines during steady state operation: overtorque detection function
  • Machines with strong risk of jamming, machines with torque build-up over time,
  • Mechanical failure monitoring,
  • Faster detection of malfunctioning on machines where the motor is oversized in relation to its thermal protection Pt.
  • Motor protection for specific applications:
  • Machines with long starting times,
  • Machines with high on-load factor: more than 30 to 50 starts/hour,
  • Machine with fluctuating load from a steady state, where the thermal image of a thermal overload relay (thermal memory) is unsuitable in relation to actual overheating of the motor.

Examples of machines:

  • Conveyors, crushers and mixers,
  • Fans, pumps and compressors,
  • Centrifuges and spin-dryers,
  • Presses, shearing machines, saws, broaching machines, sanders and lifting hoists.

Operation:

  • Because of their two separate time settings, LT47 relays can be combined with the motor-starter function:
  • D-Time: starting time, 0-Time: trip time during steady state.
  • The D-Time function is only available during the motor starting phase. During this phase the overload detection
  • function is inhibited in order to allow starting. Under steady state conditions, when the motor current is greater than
  • the setting current due to an overload or single-phasing, the red LED lights up and the internal relay switches its
  • contact after a time preset by the 0-Time knob.
  • The red LED stays on, indicating that the relay has tripped.

The relays are simple to set, in 5 easy steps:

  • Adjust the 3 knobs to maximum (Load, D-Time and 0-Time),
  • Adjust the D-Time knob to the value corresponding to the motor starting time.
  • When the motor reaches steady state, adjust the Load knob (turn the knob counter-clockwise until the red LED starts to flicker).
  • Slowly turn the Load knob clockwise until the LED goes out.
  • Set the required tripping time, using the 0-Time knob.
Technical Specifications: 

LT47 Electronic Over Current Relays

Relay setting range

Usable range (1)

Relay supply voltage

Reference

Weight

A

A



kg

LT47 relay with manual/electric reset

0.5…6

0.5…5

a 200…240 V

LT47 06M7S

0.192

a 100…120 V

LT47 06F7S

0.192

c/a 24 V

LT47 06BS

0.192

c/a 48 V

LT47 06ES

0.192

3…30

3…25

a 200…240 V

LT47 30M7S

0.192

a 100…120 V

LT47 30F7S

0.192

c/a 24 V

LT47 30BS

0.192

c/a 48 V

LT47 30ES

0.192

5…60

5…60

a 200…240 V

LT47 60M7S

0.192

a 100…120 V

LT47 60F7S

0.192

c/a 24 V

LT47 60BS

0.192

c/a 48 V

LT47 60ES

0.192