Basic System Description
A motor control system will obviously include a motor and inverter, as well as a circuit breaker or fuses for safety. If you are connecting a motor to the inverter on a test bench just to get started, that’s all you may need for now. But a system can also have a variety of additional components. Some can be for noise suppression, while others may enhance the inverter’s braking performance. The figure and table below show a system with all the optional components you might need in your finished application.
Breaker,
MCCB or
GFI
L1 | L2 | L3 |
|
| +1 |
Inverter + | ||
|
| GND |
T1 | T2 | T3 |
From power supply
|
|
Breaker / | A |
disconnect | interrupter (GFI), or a fused disconnect device. NOTE: The |
| installer must refer to the NEC and local codes to ensure |
| safety and compliance. |
This is useful in suppressing harmonics induced on the | |
AC Reactor | power supply lines and for improving the power factor. |
| WARNING: Some applications must use an |
| Reactor to prevent inverter damage. See Warning on next |
| page. |
Radio noise filter | Electrical noise interference may occur on nearby |
| equipment such as a radio receiver. This magnetic choke |
| filter helps reduce radiated noise (can also be used on |
| output). |
EMC filter (for | Reduces the conducted noise on the power supply wiring |
CE applications, | between the inverter and the power distribution system. |
see Appendix D) | Connect to the inverter primary (input) side. |
Radio noise filter | This capacitive filter reduces radiated noise from the main |
(use in | power wires in the inverter input side. |
applications) |
|
DC link choke | Suppress harmonics generated by the inverter. However, it |
| will not protect the input diode bridge rectifier. |
Radio noise filter | Electrical noise interference may occur on nearby |
| equipment such as a radio receiver. This magnetic choke |
| filter helps reduce radiated noise (can also be used on |
| input). |
This reactor reduces the vibration in the motor caused by | |
AC Reactor | the inverter’s switching waveforms, by smoothing the |
| waveform to approximate commercial power quality. It is |
| also useful to reduce harmonics when wiring from the |
| inverter to the motor is more than 10m in length. |
LCR filter | Sine wave shaping filter for output side. |
M
Thermal switch
9
