3TF power contactors from Siemens has been designed for switching and controlling squirrel cage and slip-ring motors as well as other AC loads, such as solenoids, capacitors, lighting loads, heating loads and transformer loads. SICOP contactors and bi-relays and have been tested for type-2 coordination at Iq = 50kA, 415V, 50Hz as per IS:13947, for both fuse protected as well as fuseless motor feeders.

SICOP comes in a total of 21 ratings up to 820A. These are :
• 9, 12, 16, 22, 32 and 38A – Air break contactor with DIN channel mounting / screw mounting facility
• 45, 63, 70, 75, 85, 110, 140, 170, 205, 250, 300, 400 and 475A – Air break contactor, with screw mounting facility
• 630A and 820A – Vacuum contactor with screw mounting facility

• SICOP contactors have been designed to operate even in severe operating conditions.
• Suitable for operation in service temperature up to 55 C without derating.
• The superior design of current carrying parts, contact system and the magnet system increase the reliability by offering higher electrical and mechanical endurance.
• SICOP contactors have a high short-time rating, which makes them suitable for applications having high starting currents and long run-up times.
• SICOP contactors, up to 38A are suitable for operating voltages up to 690V and the higher ratings up to 1000V. High insulation voltage and impulse withstand voltage capacity ensures reliable performance during occasional abnormal increases in supply voltage.
• Double break parallel bridge contact mechanism for auxiliary contacts. This ensures reliable contact at low voltage and low currents (5mA at 17VDC). Secondly, it offers unmatched reliability.

Many applications involve switching of heavy currents and at a high switching frequency. Also, some applications need switching in the dusty and aggressive atmosphere. Siemens offers vacuum power contactors of 630A & 820A for low voltage applications up to 1000V.

The Vacuum contactors type 3TF68 and 3TF69 offer the following benefits:
• High reliability / operational safety.
• High electrical and mechanical life
• Integral Voltage limiter, which
prevents multiple arc re-striking.
• Low coil consumption.
• Suitable for high switching
frequency applications.
• Compact design:
− Totally enclosed switching. No chances of arc coming out.
− No need for arcing clearance on the top or front.
− Maintenance free vacuum bottle (contacts).
− Contact erosion indicator indicates the state of contacts.