Weg EC-R1 Rev. Bus Bar for CWB Contactors

The Weg EC-R1 and EC-R2 reversing bus bars for CRB contactors provide an easy means of building a reversing contactor for 3-phase electric motors. The EC-R1 is for CWB contactors from 9 to 38 Amps, and the EC-R2 is for CWB 40+ amp contactors

How to Build a Reversing Contactor

Items Needed

• 2 Weg CWB contactors, appropriately sized for the motor current.
• 1 Weg IM1 or IM2 interlock, depending on contactor size
• 1 set of Weg Bus bars, either EC-R1 or EC-R2
• (optional-strongly advised) Motor Overload Protection Relay, such as the Weg RW27 or RWB series

Steps (see assembly photo):

1. Mount the two CWB contactors side-by-side with the mechanical interlock sandwiched in-between.
2. Attach the bus bar with the two small tabs on the top of thetwo contactors
3. Attach the bus bar without any tabs to the bottom of the two contactors
4. Connect the two coils up to the appropriate switches or other controls
5. Connect incoming power, appropriately fused, to the top of the left contactor
6. Connect the motor leads to the bottom of the left contactor
7. Optional: Connect overload relay to bottom of left contactor, then connect motor leads to bottom of overload relay. Wire overload relay contacts appropriately with control to the contactor coils (beyond scope of this guide).

NOTES:

• Do not switch the top and bottom bus-bars. The tabbed one must be on top or a short-circuit will result.
• A Motor overload protection relay is strongly advised to protect the motor from over-current and phase loss

Documentation

• Weg CWB Flyer
• Weg CWB & RW27 Catalog