© 2016 OJ Electronics A/S
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INSTRUCTIONS OJ-DV | Functions
Before operation, select and load the correct fan and motor parameter files using the OJ-DV
Handterminal or OJ-DV-PCTool. It is the installer’s responsibility to enter the correct control and
motor parameters.
Pay special attention to the following parameters:
Minimum rpm Even if the control signal is e.g. 0% or 0.0V and the OJ-DV has an activated start signal, the motor will not
run slower than the value in this parameter.
Maximum rpm Even if the control signal is e.g. 100% or 10.0V and the OJ-DV has an activated start signal, the motor will
not run faster than the value in this parameter.
Ramp-up time Ramp-up time is the time (in seconds) between the OJ-DV gets the start signal until the speed has been
reached according to the setpoint.
The ramp-up time is used to avoid overload and damage to the controller and motor. The ramp-up time is
also used in upwards jumps between speed setpoints.
If this ramp up is too short, the OJ-DV possibly could trigger an current limit alarm.
Ramp-down time Ramp-down time is the time (in seconds) from when the OJ-DV receives a stop signal until the motor comes
to a halt. The ramp-down time is used to avoid overload and damage to the controller and motor. Ramp-
down time is also used in connection with downward jumps between speed setpoints.
If this ramp-down is too short, the OJ-DV will use power to stop or slow down the motor. This could possibly
trigger a high voltage alarm (Vhi), from the OJ-DV.
Switch frequency Switch frequency is a parameter that has an influence on the eciency and the audible noise from the con-
nected motor and/or the OJ-DV controller.
In the OJ-DV it is possible to select “Auto”, “4 kHz” and “8 kHz”.
The higher the switch frequency, the lower the audible noise from the OJ-DV controller system, but the con-
sequence of lower audible noise is decreasing eciency of the OJ-DV controller system.
In “Auto” the OJ-DV will automatically switch between “4 kHz” and “8 kHz”. During start-up from 0 - 60%
speed, the switch frequency will be “8kHz” and this will make for less audible noise from the connected
motor and/or the OJ-DV controller. When the speed has increased and passes 60%, the switch frequency
will then switch to “4 kHz”. The noise from the fan and airflow will now drown out the audible noise from the
OJ-DV controller system.
In the speed-down sequence, the OJ-DV will switch to “8 kHz” when the speed of the motor passes 50%
downwards.
It is also possible to select a fixed switch frequency of “4 kHz” or “8 kHz”.
In the speed-down sequence, the OJ-DV will switch to “8/10 kHz” when the speed of the motor passes 50%
downwards.
It is also possible to select a fixed switch frequency of “4 kHz” or “8/10 kHz”.
For further information about parameters in the OJ-DV, see OJ-DV Modbus protocol.
19. Built-in protection
• If the temperature inside OJ-DV exceeds 95°C, OJ-DV will attempt to reduce its internal heat
generation by reducing motor speed (rpm).
• OJ-DV has built-in current limitation for the protection of motor and cables and cannot therefore
supply more current than it is set to.
• In the event of lacking phase on the supply input, OJ-DV will reduce speed and activate a non-
critical alarm.
• The OJ-DV motor output terminals are short-circuit protected against phase-to-phase short
circuiting.
20. Alarms
• OJ-DV has a built-in alarm monitor, which monitors optimal fault-free operation and triggers an
alarm if operating or performance problems are observed.
• Alarms are either ”Critical” alarms or ”Non-critical” alarms.
• ”Critical” alarms stop the motor.
• ”Non-critical” alarms reduce motor performance.
• The built-in alarm monitor stops the OJ-DV.
• If the alarm situation passes, the alarm is automatically reset and OJ-DV restarted.
• If the maximum number of restarts (5 times/60 min) is exceeded, the alarm must be reset
manually.
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