There are two main types of variable frequency drive bypass options: conventional and electronic. Conventional bypass uses hard-wired electrical components like switches, fuses, and relays for mechanical bypass control. Electronic bypass uses electronic logic control with a simple keypad and has reduced wiring and mechanical components for improved reliability. Electronic bypass components include a control board, output contactor, motor overload relay, and optional line reactor. The electronic keypad displays status and operating configuration using LED indicators and buttons to control the input contactor, enable functions, and hand/remote bypass modes.

1. Variable Frequency Drives Bypass Options

2. Two Contactor Bypass VFD Bypass Operation SED2 Drive Motor Power Supply Drive Output Contactor Bypass Contactor Mechanically Interlocked

3. Three Contactor Bypass SED2 Drive Motor Power Supply Drive Output Contactor Bypass Contactor Mechanically Interlocked Optional Input Contactor VFD Bypass Operation Optional “3 rd ” drive input contactor electrically isolates the VFD

6. Conventional Bypass Components Mounting Back Plate Drive Test Selector (3 contactor only) Drive /Off / Bypass Selector Bypass ON Indicator Light Line Disconnect Gland Plate Protective cover Conduit Connector

7. Conventional Bypass Components Line reactor (optional) Input contactor (optional) Control transformer Power fuses (optional) Line disconnect Control relays Field wiring terminals Motor overload relay Bypass contactor Output contactor

8. Conventional Bypass Power Range A-F denotes VFD frame size For more info, see the Bypass menu on this CD

10. Electronic Bypass Components Control transformer Output contactor Motor overload relay Line reactor (optional) Input contactor (optional) Power fuses (optional) Line disconnect Bypass contactor Field wiring terminals Electronic control board

12. Electronic Bypass Keypad Features Indicates that input contactor is closed and drive has power. Toggling this button opens / closes the input contactor. Enable closes both drive input and output contactors. Essential service light flashes when this feature is activated. Disconnect the motor whether in drive or bypass mode. Indicates input contactor is closed when on, close pending when flashing. Enables hand bypass mode. Enable remote bypass. Bypass light w/ flash. Contactor closes and light comes on when Remote Start input closes. Auto Bypass light flashes when this feature is activated. Indicates that one of the safety inputs is open. Indicates that either the overload input has closed or that the thermal overload has tripped. Indicates present operational state of interlocked start logic.

13. Electronic Bypass Power Range A-F denotes VFD frame size For more info, see the Bypass menu on this CD