Protection Features - Danfoss iC2-Micro Series Design Manual

Design Guide | iC2-Micro Frequency Converters
Resistor Braking
3.6.5.2
In applications where fast or continuous braking is required, a drive fit with a brake chopper is typically used. Excess energy generated
by the motor during braking of the application will be dissipated in a connected brake resistor. Braking performance depends on the
specific drive rating and selected brake resistor.
Overvoltage Control (OVC)
3.6.5.3
If braking time is not critical or the load is varying, the overvoltage control (OVC) feature is used to control stopping the application. The
drive extends the ramp-down time when it is not possible to brake within the defined ramp-down period. The feature should not be
used in hoisting applications, high-inertia systems, or where continuous braking is required.
3.6.5.4 DC Brake
When braking at low speed, the braking of the motor can be improved by using the DC brake feature. It adds a small DC current on top
of the AC current, slightly increasing the brake capability.
3.6.5.5 AC Brake
In applications with non-cyclic operation of the motor, AC braking can be used to shorten the braking time and is only supported for
induction motors. Excess energy is dissipated by increasing losses in the motor during braking.
3.6.5.6 DC Hold
DC hold provides a limited holding torque on the rotor at standstill.
Load Sharing
3.6.5.7
In some applications, 2 or more drives are controlling the application at the same time. If 1 of the drives is braking a motor, the excess
energy can be fed to the DC link of a drive driving a motor, with a reduction of the total energy consumption. This feature is useful in, for
examples, decanters and carding machines, where smaller power-sized drives operate in generator mode.

Protection Features

3.6.6
Grid Protections
3.6.6.1
The drive protects against conditions on the power grid that can affect proper operation.
The grid is monitored for phase imbalance and phase loss. If the imbalance exceeds internal limits, a warning is provided and the user
can initiate proper actions.
In case of an under- or overvoltage on the grid, the drive will provide a warning and stop operation if the situation remains or exceeds
critical limits.
Drive Protection Features
3.6.6.2
The drive is monitored and protected during operation.
Inbuilt temperature sensors measure the actual temperature and provide relevant information to protect the drive. If the temperature
exceeds its nominal temperature conditions, derating will be applied. If the temperature is outside the allowed operating range, the
drive will stop operation.
The motor current is continuously monitored on all 3 phases. In case of a short circuit between 2 phases or a fault to ground, the drive
will detect this and immediately turn off. If the output current is exceeding its nominal values during operation for longer periods than
allowed, the drive will stop and report overload alarm.
The DC-link voltage of the drive is monitored. If it exceeds critical levels, a warning is issued and the drive will stop. If the situation is not
resolved, the drive will issue an alarm.
30 | Danfoss A/S © 2024.08
iC2-Micro Frequency Converters
AJ402315027937en-000401 / 130R1239