STEP ET Series - Connection of Main Circuit Peripheral Devices

Chapter 4 Wiring of Inverter
Shanghai Sigriner STEP Electric Co., Ltd.
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4.1.2 Connection of main circuit peripheral devices
4.1.2.1 Input power connection
The inverter cannot be operated outside the rated input line voltage range; overvoltage may
cause permanent damage to the inverter.
Table 4-1 Technical requirements for input power
Technical requirements for input power (main circuit) connection
Input voltage
Voltage is three-phase 380~480VAC, -15%~+10%
Short-circuit current
(IEC60909 standard)
If the incoming cable of the inverter is protected by a suitable fuse, then the
maximum allowable short-circuit current is 100kA within 1s
Frequency
50~60Hz, -5%~+5%
Unbalance degree
Maximum ±3% of rated input line voltage
Cable temperature
Min. rated value: 90°C
4.1.2.2 Input protection
Input protection includes circuit breakers, fuses, emergency stop devices, etc.
Circuit breaker
The inverter itself does not include disconnection device. Therefore, a disconnection device must be
installed between the AC input power and the inverter. This disconnection device must conform to
the following requirements:

The device shall comply with safety regulations of the actual application, including (but
not limited to) national and local electrical regulations.

The disconnection device must stay in the off position and locked out during installation
and maintenance of the inverter.
 The disconnection device should not be used to control the start/stop of the motor. The
motor should be controlled using the operator keys, or commands from the I/O terminals.
 The capacity of the circuit breaker should be selected as 1.5 to 2 times the rated current of
the inverter.

The time characteristics of the circuit breaker should take full account of the time
characteristics of the inverter overheating protection (150% of the rated output current for
1 min).
Fuse
The end user must provide a circuit protection device and the device should be selected in
accordance with national and local electrical regulations. Table 4-2 provides the recommended fuse
types to offer short circuit protection for the incoming power section of the inverter.
Table 4-2 Recommended fuse models (the recommended fuse Bussmann meets UL certification)
Inverter
model
EP6/ET6
inverter
capacity
(kW)
EH6
inverter
capacity
(kW)
Main fuse
Model
4T4A1
1.1
1.5
10
FWP-10B
4T5A6
1.5
2.2
15
FWP-15B
4T7A2
2.2
3
15
FWP-15B
4T9A4
3
4
20
FWP-20B
4T012
4
5.5
30
FWP-30B
4T018
5.5
7.5
40
FWP-40B