Veichi AC90 Manual page 73

AC90 TENSION CONTROL FREQUENCY INVERTER MANUAL
one frequency inverter will bring 100mA leakage current (while the power cable length is 1m). If the length prolongs 1m,
there will be 5mA more leakage current. So please use leakage current breaker special for high frequency leakage at
the power input side of the frequency inverter. The factors which impact leakage current are as follows:
Capacitance of inverter;
Carrier frequency;
Motor cable type and wire length;
MI/RFI filter.
To protect human body and inverter, pleast choose leakage current breaker which can use AC/DC power and can reply
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 will be
higher, what will make the breaker malfunction. At this case, please take following treatments:
Improve the sensitive current of the leakage current breaker;
Reduce the carrier frequency of the inverter.
Electromagnetic contactor
③
Electromagnetic contactor is a peripheral equipment what is set to separate power and inverter connection. While
inverter protective function is acting or carring 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 maybe 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
④
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 ultraharmonics current and improve power side factor;
Need to switch input phase capacitance;
When 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 connecting
the external DC reactor, make sure to dismantle the short connector between the terminals P1 and (+).
Surge restrainer
⑤
Surge restrainer is divided to 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 restraining 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, electromagnetic
detent). 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
⑥
Rectifier bridge of the inverter is uncontrolled rectifier. And input current is discontinuous impulse current. So the
harmonic current noise signal, what flows to power wire from the inverter inner, maybe bring bad impact on the
surrounding machines (radio, phone, noncontact switch, sensor). This time, we suggest to instal 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 special noise filter for the frequency inverter and the connection wire between the filter
and the inverter should be as short as possible.
Output side noise filter
⑦
The frequency inverter outputs square wave with high-speed peak value voltage switch. So there is high-speed dv/dt
conver on the output cables that will produce a large number of radio disturbance and inductive signal. By installation
BASIC OPERATION AND TRIAL RUN
68