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BCH Electric Limited is known as the best manufacture & Supplier of Thermal Overload Relays. We offer high quality of relays that are highly sophisticated and efficient for industrial purposes. To know more about range visit our site now.
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Welcome you all.. in the training session on Thermal Overload relay BCH ELECTRIC LTD www.bchindia.com
Thermal Overload Relays Contents: A. Basics & Standards B. Range & Selection
Relays Basics of Thermal OLR Thermal Overload Relay Thermal overload relay is a protective device. It is designed to cut power if the motor draws too much current for an extended period of time. Thermal relays use a bimetallic strip to mechanically open the contacts. Bimetallic strips consist of two conjoined pieces of metal which expand at different rates when exposed to heat. This difference, forces the strip to bend when heated. This strip is attached to a contact by a spring. When excess heat generated due to overcurrent, it causes the strip to bend and pull the spring, hence contacts are pulled apart and circuit gets broken. When the strip is cooled it returns to its original shape. * Trip Classes 10A 10 20 30 Tripping time in Sec at 7.2 times of setting current (in cold state) 2 to 10 sec 4 to 10 sec 6 to 20 sec 9 to 30 sec Thermal OLR specification: Full load current range Control Voltage Trip class*
Relays Range & Selection Range of BCH Thermal OLR (1) Citation-M overload relays (2) Duros Freedom overload relays Wide range: 0.195A to 600A Built-in single phasing protection Ambient temp compensated Direct & individual mounting Conforms to IEC 60947-4-1 Relay class-10 Range: 0.1 to 32A Built-in single phasing protection Ambient temp compensated Direct & Individual mounting Conforms to IEC 60947-4-1 Relay class-10A
Relays Range & Selection Selection chart for Citation-M relays Direct operated relays CT operated relays Full load current range (A) 0.195 — 0.31 0.30 — 0.48 0.47 — 0.75 0.75 — 1.14 1.07 — 1.70 1.58 — 2.50 2.40 — 3.80 3.80 — 6.00 6.00 — 9.30 8.90 — 13.5 13.20 — 20.0 17.40 — 24.0 22.0 — 30.0 Full load current range (A) 24.4 — 39.0 37.6 — 60.0 56.4 — 90.0 84.6 — 135.0 131.6 — 210.0 188.0 — 300.0 263.2 — 420.0 376.0 — 600.0 Cat code Cat code MC305ANA3A MC305ANA3B MC305ANA3C MC305ANA3D MC305ANA3E MC305ANA3F MC305ANA3G MC305ANA3H MC305ANA3J MC305ANA3K MC305ANA3L MC305ANA3M MC305ANA3N CT1MC305ANA3C CT2MC305ANA3C CT3MC305ANA3C CT4MC305ANA3C CT5MC305ANA3C CT6MC305ANA3C CT7MC305ANA3C CT8MC305ANA3C
Relays Range & Selection Selection chart for Duros Freedom Relays (MC318ANA) Full load current range (A) Cat code 0.10 — 0.16 0.16 — 0.25 0.25 — 0.40 0.40 — 0.63 0.63 — 1.00 1.00 — 1.40 1.30 — 1.80 1.70 — 2.40 2.20 — 3.10 2.80 — 4.00 3.50 — 5.00 4.50 — 6.50 6.00 — 8.50 7.50 — 11.00 10.00 — 14.00 13.00 — 19.00 18.00 — 25.00 24.00 — 32.00 MC318ANA3A MC318ANA3B MC318ANA3C MC318ANA3D MC318ANA3E MC318ANA3F MC318ANA3G MC318ANA3H MC318ANA3J MC318ANA3K MC318ANA3L MC318ANA3M MC318ANA3N MC318ANA3P MC318ANA3Q MC318ANA3R MC318ANA3S MC318ANA3T * Use an Adapter (C318F1) for individual mounting