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LFD series auxiliary switch

Rated Voltage:DC 220V AC 500V

Rated Current:20A

Conventional Thermal Current:25A

Breaking Capacity:T0.95:6P=300ms 4A Cosφ=0.95 15A

Ambient Temperature:-40℃~+70℃

Withstand Voltage:2500V(50Hz) /1min

Life Cycle:20000次


General Instruction
LFD series auxiliary switch is one of the auxiliary components for the set of high-voltage equipments. With the compact structure and 6.5mm thickness of each section of switch (half of the normal auxiliary switch section), It adopts the cam composition and permanent magnet magnetic quenching method which enhance the breaking capacity of the contacts. LFD series auxiliary switch is applicable both for controlling switch on & off functions, interlocking, signal circuit of high-voltage-switch driving mechanism and for conversions or group switches.
Service Condition

1.Ambient temperature : -40℃~+70℃;
2.Altitude : the installation spot is supposed not to exceed 5000m;
3.Humidity : the average value of relative humidity is max 95%,the average value of vapor pressure is max 2.2kPa in condition within 24 hours; the monthly average value of relative humidity is max 90%,the monthly average value of vapor pressure is max 1.8kPa;
4.Vibration acceleration is max 15m/s2;
5.There should be no evident air pollutions from dust, smoke, corrosives and combustible gas, vapor or salty fog.


Meaning of the Symbol

E.g.: model no.LFD-40Y01 means LFD series  , screw connection mode, 40 pairs 
of contacts

Technical Parameters

額定電流 Rated current


約定發熱電流 Conventional thermal current


額定電壓 Rated voltage

直流 DC

交流 AC



開斷容量 (>1°/ms) 

Breaking capacity  (>1°/ms)

T0.95 6P=300ms




工頻耐壓 Withstand voltage

2500V(50Hz) /1min

機械壽命 Life cycle



Structure Features
LFD series auxiliary switch has the advantages of flexible operation, compact structure, safe and reliable. LFD series auxiliary switch is made up of multi-units with same structures and the switch installation is in various forms and suitable for  many kinds of installation assembling.  It adopts permanent magnet magnetic quenching method to enhance the breaking capacity of the switch .The moving contact is made of pure brass and the contact point adopts silver and nickel alloy with the high breaking capacity and long life-time .The insulation plate is made of superior imported inflaming resistance nylon material which has high strength, good insulation ,heat-resistant and dustproof structure. It can be used on all kind of electrical equipments.


Working Principles
LFD series auxiliary switch adopts indirect driving structure , it is working by square shaft to drive the cam wheel rotated, which in turn to push rod of switch to cause the moving of the contacts, thus to realize the control of the switch on & off the electric circuits.


Installation and Operation
1.Please refer to switch draft for mounting dimension;
2.The auxiliary switch should be installed to the target objects by fixing the extended screw shaft at both sides of the end plates .The switch itself should not be subject to external force,otherwise, it will become deformed and not able to work normally;
3.Lead wire for LFD series auxiliary switch should be adopted screw connecting method.

Ordering Information
1.Pls indicate product name, specification & model No. ,quantity;
2.Pls make sure the dimension of switch, work route and breaking of contacts etc;
3.Other requirements.

Construction Drawing 

n=insulation plate quantity; L,L1,L2=customer's requirements.