Libratherm Instruments Private Limited

Features:

• Designed to Trigger 25 Amps to 1000 Amps SCR-SCR modules.
• Suitable for 3 phase AC Induction motor up to 300HP (225KW)
• User selectable configuration for 3 wire close delta and 6 wire open delta
• User settable jump start and soft start / ramp time
• Accepts start and stop command from external potential free contact
• Current Limit and Over load trip facility
• Contactor bypass output and Fault output

Description:

To gradually accelerate the speed of 3 phase AC induction motor it is required to feed gradually increasing voltage to the motor and such behavior is only possible by connecting SCRs in series with the motor. The SCRs are controlled by MSST-15 card to generate the firing pulses giving the effect of soft start and thereby to reduce the starting current. Libratherm offers SCR triggering card model MSST-15, which is specially designed for 3 phase AC motor soft starter application. This card accepts the start/stop command from DOL switch to gradually run the motor and stop the motor. User has access to set the starting voltage to create the initial jump start to overcome the torque and to set the soft start time. The card takes the feedback from 5A CT to monitor the motor current and to generate the trip contact in case of motor over load condition occurs due to any reason. Once the motor achieves full rotational speed, it is not mandatory to pass the current through the SCRs and hence these SCRs can be by passed using external contactor. The bypass command in the form on C-NO contact is generated by MSST-15, once the full speed is achieved as indicated by TOR LED. This contact can be used to turn on external bypass contactor.

The MSST-15 card works on Auxiliary supply of 230VAC. User can build motor soft starter just by using MSST-15 card and suitable ratings of external thyristors, based on the motor capacity.

We are the leading supplier of SCR Triggering Card With Current Limit and Trip LTC-13. Clients can avail the products at best market prices.



Features:

• Designed to fire 25 Amps to 1000 Amps SCR-SCR modules of Semikron, IXYS, IR, Eupac, Hind Rectifier and Ruttonsha or any other make.
• Single phase / 2 phase / 3 phase versions.
• Suitable for both star or delta or rectifier load configurations.
• Suitable for single phase or three phase Heaters, Transformers, DC rectifiers
• Soft starter for 3 phase AC induction motor. (Our card MSST-15)
• Auto / Manual operation.
• Accepts (4-20)mA / (0-5)VDC / (0-10)VDC control inputs
• Soft start for smooth control.
• Adjustable power and current limit.

 

Libratherm offers SCR triggering cards model LTC-13 which are designed to fire or trigger back to back connected SCRs using synchronized phase angle control technique. The card accepts analogue control signals of (0-5)/(0-10)VDC or (4-20)mA and provides proportional gate/cathode triggering pulses G1K1 + G2K2. These pulses can be used to trigger back-to-back connected SCRs upto 1000Amps with gate current upto 300mA. The card also provides built in regulated 5VDC supply to connect external potentiometer to manually control the SCR firing. The on card ramp up and ramp down settings allows gradual rise and fall of the voltage levels across the load.

Many times it is required to limit the current flowing through the load. Such current limiting feature is available in LTC-13 – for single phase and two phase load. Whereas for 3 phase load, common three phase current limiting is achieved by LTC-18 card. The load current or Line current feedback is derived from the external CTs. This feature is useful for transformer load or inductive loads or for heating elements like Silicone Carbide and Molybdenum Disilicide, which exhibits significant change of resistance with increase in temperature. This feature will restrict the maximum load current to the value set using the on card current limit (CL) potentiometer. On sudden increase in the current the current trip feature will over-ride the current limit feature and the firing of the thyristor will stop instantly. The trip contacts are available on the terminals.

Features:

• Designed to fire 25 Amps to 1000 Amps SCR-SCR modules of Semikron, IXYS, IR, Eupac, Hind Rectifier and Ruttonsha or any other make.
• Single phase / 2 phase / 3 phase versions.
• Suitable for both star or delta or rectifier load configurations.
• Suitable for single phase or three phase Heaters, Transformers, DC rectifiers
• Soft starter for 3 phase AC induction motor. (Our card MSST-15)
• Auto / Manual operation.
• Accepts (4-20)mA / (0-5)VDC / (0-10)VDC control inputs
• Soft start for smooth control.
• Adjustable power and current limit.

Description:

Libratherm offers SCR triggering cards model LTC-15 which are designed to fire or trigger back to back connected SCRs using synchronized phase angle control technique. The card accepts analogue control signals of (0-5)/(0-10)VDC or (4-20)mA and provides proportional gate/cathode triggering pulses G1K1 + G2K2. These pulses can be used to trigger back-to-back connected SCRs upto 1000Amps with gate current upto 300mA. The card also provides built in regulated 5VDC supply to connect external potentiometer to manually control the SCR firing. The on card ramp up and ramp down settings allows gradual rise and fall of the voltage levels across the load.

Many times it is required to limit the current flowing through the load. Such current limiting feature is available in LTC-13  for single phase and two phase load. Whereas for 3 phase load, common three phase current limiting is achieved by LTC-18 card. The load current or Line current feedback is derived from the external CTs. This feature is useful for transformer load or inductive loads or for heating elements like Silicone Carbide and Molybdenum Disilicide, which exhibits significant change of resistance with increase in temperature. This feature will restrict the maximum load current to the value set using the on card current limit (CL) potentiometer. On sudden increase in the current the current trip feature will over-ride the current limit feature and the firing of the thyristor will stop instantly. The trip contacts are available on the terminals.