AC70 VC CONTROL FREQUENCY INVERTER MANUAL
PERIPHERAL EQUIPMENTS AND OPTIONS
67
MI/RFI filter
To protect human body and inverter, please choose leakage current breaker which can use AC/DC power and can face
high frequency leakage current. There should be one leakage current breaker with more than 200mA sensitive current
for every frequency inverter. If the frequency inverter outputs different wave, the high frequency leakage current can be
higher, which will lead to breaker fault. In this case, please take below treatments:
Improve the sensitive current of the leakage current breaker
Reduce the carrier frequency of the inverter
Electromagnetic contactor
Electromagnetic contactor is a peripheral equipment what is set to actually separate power and inverter connection.
While inverter protective function is acting or carrying out emergency stop operation, the main loop power can be cut by
peripheral equipment. Please do not connect the electromagnetic switch or electromagnetic contactor to output circuit.
Otherwise the inverter may be damaged. While the power recovers after instant stop, if it needs to prevent the inverter
to auto-restart, please install electromagnetic contactor for control at the input side.
AC input reactor and DC reactor
To restrain current sharp change and high hypo harmonic current, it needs to use AC input reactor and DC reactor. It
can also improve power factor at the input side. In the following cases, AC input reactor or DC reactor must be used
(use both will bring better effect).
Need to restrain high hypo harmonic current and improve power side factor;
Need to switch input phase capacitance;
Frequency inverter is connected to large capacitance power transformer (600kVA above);
Silicon-controlled converters such as DC motor driver are connected to the same power system.
If user has higher requirement on other harmonic restraint, please connect the external DC reactor. Before connect the
external DC reactor, make sure to dismantle the short connector between the terminals P1 and (+).
Surge restrainer
Surge restrainer is divided into winding surge restrainer and main loop surge restrainer according to the use position.
Pls choose the right one which is suitable for the occasion. The aim of surge restrainer installation is to restrain the
surge voltage brought by switch components such as inductive load which is surrounding the frequency inverter
(electromagnetic contactor, electromagnetic relay, electromagnetic valve, electromagnetic winding). Do not connect the
surge restrainer to the output side of the frequency inverter. Otherwise the frequency inverter will be damaged.
。
Input side noise filter
Rectifier bridge of the inverter is uncontrolled rectifier bridge. And input current is discontinuous impulse current. So the
harmonic current noise signal, which flows to power wire from the inverter inner, may bring bad impact on the
surrounding machines (radio, phone, non contact switch, sensor). This time, we suggest to install input side noise filter
to lighten the noise into the power wire. Besides, it can also reduce noise from the power wire into the frequency
inverter.
: Please use the noise filter special for the frequency inverter and the connection wire between the filter and
the inverter should be as short as possible.
Output side noise filter
The frequency inverter outputs square wave with high-speed peak value voltage switch. So there is high-speed dv/dt
converter on the output cables that will produce a large number of radio disturbance and inductive signal. By installation
noise filter at the output side, the impact can be relieved. Please do not install the input-phase capacitance and the
noise filter to the output circuit. Otherwise there is danger of damage to the frequency inverter.
0-phase reactor
0-phase reactor is used to reduce the electromagnetic inductive disturbance of the frequency inverter, which is suitable
for the input side and output side. It equals to a three-phase common mode inductance. In actual use, according to the
actual magnetic core size and cable specification, it is better to make sure 3-5 circles winding ratio to bring the best
performance.
Braking reactor or braking unit
Renewed power consumption unit, please see the sixth part of the chapter three “electric installation”.
Heat relay
Please install the heat relay at the output side of the frequency inverter. When the motor enters into overload state, it
will cut the power source to protect the motor. While using one frequency inverter to run one motor, there is no need to
install heat relay. The motor overload protection current [E-49] of the frequency will work. While using one frequency
inverter to run multi-motors or the motor is run directly by the power grid, please install heat relay between the
frequency and the motor. While installing the heat relay, please design to cut the sequence control circuit of the MC at
the main loop input side by the connection spot of the relay or design to input the heat relay action into the frequency
inverter as the exterior malfunction.And please pay attention to the following tips to avoid heat relay fault and motor
overheating at low speed.
