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5.13 Electromagnetic/Induction Noise
There are many noises surround the AC motor drives and invade it by radiation or power circuit. It
may cause the misoperation of control circuit and even damage the AC motor drive. Of course, that is
a solution to increase the noise tolerance of AC motor drive. But it is not the best one due to the limit.
Therefore, solve it from the outside as following will be the best.
1.
Add surge suppressor on the relay or contact to suppress switching surge between ON/OFF.
2.
Shorten the wiring length of the control circuit or serial circuit and separate from the main AC
circuit wiring.
3.
Comply with the wiring regulation for those shielded wire and use isolation amplifier for long
wire length.
4.
The grounding terminal should comply with the local regulation and ground independently, i.e.
not to have common ground with electric welding machine and power equipment.
5.
Connect a noise filter at the input terminal of the AC motor drive to prevent noise from power
circuit.
In a word, three-level solutions for electromagnetic noise are "no product", "no spread" and "no
receive".
5.14 Environmental Condition
Since the AC motor drive is an electronic device, you should comply with the environmental
conditions. The following steps should also be followed.
1.
To prevent vibration, anti-vibration spacer is the last choice. The vibration tolerance must be
within the specification. The vibration effect is equal to the mechanical stress and it cannot
occur frequently, continuously or repeatedly to prevent damaging to the AC motor drive.
2.
Store in a clean and dry location free from corrosive fumes/dust to prevent corrosion and poor
contacts. It also may cause short by low insulation in a humid location. The solution is to use
both paint and dust-proof. For particular occasion, use the enclosure with whole-seal structure.
3.
The surrounding temperature should be within the specification. Too high or low temperature
will affect the lifetime and reliability. For semiconductor components, damage will occur once
any specification is out of range. Therefore, it is necessary to clean and periodical check for the
air cleaner and cooling fan besides having cooler and sunshade. In additional, the
microcomputer may not work in extreme low temperature and needs to have heater.
4.
Store within a relative humidity range of 0% to 90% and non-condensing environment. Do not
turn off the air conditioner and have exsiccator for it.
Revision July 2008, EG03, SW V1.06
Chapter 5 Troubleshooting |
5-9
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