Ac Brake; Dc Hold; Load Sharing; Protection Features - Danfoss iC7 Motion Series Application Manual

Application Guide | iC7 Series Motion

AC Brake

2.5.5
In applications where the operation of the motor is non-cyclic, AC braking can be used to shorten the braking time. Excess energy is
dissipated by increasing losses in the motor during braking. Performance is motor type dependent and offers best performance on
asynchronous motors.

DC Hold

2.5.6
The software offers the possibility to configure the feature DC Start for DC holding before entering normal motor control.

Load Sharing

2.5.7
In some applications, 2 or more drives control 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, which results in a reduction of the total energy consumption. This feature is typically
useful in, for example, decanters and carding machines, where smaller power-sized drives operate in generator mode.

Protection Features

2.6

Grid Protection

2.6.1
The drive protects against conditions in the power grid that can affect proper operation. The grid is monitored for phase imbalance and
phase loss. When the imbalance exceeds specified limits, the drive issues a configurable response and corrective actions can be taken.
The supply frequency is also monitored, and when the drive is outside acceptable limits, it reacts in the configured way. Furthermore, the
software of the drive offers optional protection against undervoltage and a configurable response to grid spikes.

Drive Protection Features

2.6.2
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 of operational parameters is applied. If the temperature is outside the allowed
operating range, the drive stops operation.
The motor current is continuously monitored on all 3 phases. If there is a short circuit between 2 phases, or a fault to ground, the drive
detects the short circuit and immediately turns off. If the output current is exceeding its nominal values during operation for longer
periods than allowed, the overload capability is reduced until the conditions are restored.
The DC-link voltage of the drive is monitored. If it exceeds critical levels, the drive issues a warning. If the situation is not resolved, the
drive stops operation.

Motor Protection Features

2.6.3
The drive provides various features to protect the motor and the application.
The output current measurement provides information to protect the motor. Overcurrent, short circuit, ground faults, and lost motor
phase connections can be detected and relevant protections initiated.
Monitoring of speed, current, and torque limits provides an extra protection of the motor and the application. Under extreme load
conditions, it also provides motor stall protection.
Locked-rotor protection secures that the drive is not starting with a blocked rotor of the motor.
Motor thermal protection is provided either as a calculation of the motor temperature based on the actual load, or by external
temperature sensors connected to Temperature Measurement OC7T0. Supported sensor types are Pt100, Pt1000, Ni1000, KTY84, and
KTY81.
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