Emerson Unidrive M400 - Control Modes of the Electronic Bypass; Failure and Power off Conditions; Motor Overload; TEST Mode

26 Electronic Bypass Controller Installation and Commissioning Guide
Remote bypass input (TB3-1): can be used to override the keypad selections
and force the electronic bypass into Bypass Mode from an external contact. Once
this signal is removed, the electronic bypass will not return to its previous mode of
operation without keypad interaction.
Remote VFD input (TB3-2): works just like the remote bypass input by forcing the
electronic bypass into VFD Mode. The electronic bypass will not return to its previous
mode when the signal is removed.
4.5 Motor Overload
Motor Overload is generated by the overload relay built into the electronic bypass.
Should this relay operate, the motor will stop independent of its mode of operation.
The motor cannot be restarted while the MOTOR OVERLOAD indicator is illuminated.
Once the relay is reset, operation can be restored by reselecting a run mode from the
keypad.
4.6 Failure and Power Off Conditions
Should the electronic bypass control card fail such that it cannot process inputs,
the control card has an alternative mechanism for controlling the bypass contactor.
Jumpers J5, J6, and J7 control the input, bypass and output contactors respectively.
Moving any of these jumpers from the default “open” position to the “emergency”
position will force the associated contactor to be energized. This will happen
irrespective to any logic damage on the bypass board. See section 3.8.3 for details. An
interlock prevents the closing of the 3 contactors at once.
In the event the bypass control board should lose power, its EEPROM memory retains
the last operating conguration, which is restored on the next power-up.
4.7 Control Modes of the Electronic Bypass
When power is initially applied, the green main POWER ON LED is illuminated and
will remain on as long as power is connected. The OFF/RESET will be the only other
LED illuminated. The input contactor remains OFF. The VFD will have no power and its
display will remain blank. A VFD or bypass mode must rst be selected, followed by a
command in Start Auto or Hand Mode.
4.7.1 TEST mode
In Test Mode the functionality of the VFD, external speed reference devices, and
system setup characteristics can be read, set and modied. In Test Mode the input
contactor is energized. Note that the Test Mode and Bypass Mode can be operated
simultaneously if desired.
To place the VFD package in Test Mode, press the TEST button. The TEST and INPUT
CONTACTOR LEDs will be illuminated.