How selecting the right drive brings long-term benefits
ABB has produced a technical guide to help users select the correct micro drive from the ACS 55, ACS150, ACS355 and ACS 310 Series. Correctly selected and tuned motor control works better in applications and ensures correct operation in abnormal situations.
There might be different external and internal conditions that need to be considered when selecting the drive to run a machine or process. When aiming for long-term reliability, these conditions might affect the rating of the drive. Dimensioning the drive correctly involves a process of derating the continuous drive output current (motor current) or by selecting auxiliary devices such as chokes or RFI filters. A drive which is correctly dimensioned will work properly throughout its lifetime.
Derating must be taken into account when using the drive in conditions as those shown in the table below. Conditions that are often forgotten are the application cyclicity and switching frequency. Ambient temperature or other environmental conditions such as dust or humidity might also be unknown, especially when a drive is not installed by the machine builder, rather than the end-user.
It is very important to identify all derating factors in order to reach a reliable solution. For example, when a drive is installed in a cabinet, the drive and other devices heat up the cabinet to a level that can be double the operating ambient temperature. Correctly dimensioning a drive saves time and cost, and improved reliability.
Conditions that require special consideration
The technical guide provides further information on selecting ABB micro drives under the following operating conditions.
Open the ABB micro drives dimensioning guide here See more ABB micro drives at 999 Inverters
Operation condition |
Description |
Outcome |
|
| Ambient temperature | Refers to the cabinet temperature in IP20 drives and the room temperature in wall-mounted drives. | Derating needed above 40 °C | |
| Switching frequency | The higher the switching frequency of the drive is, the more the power semiconductors heat up. | When using a higher switching frequency, a drive’s output current needs to be derated. | |
| Altitude | Low air pressure decreases the cooling capability of air and air insulation. | Derating above 1000 m and PELV above 2000 m to be considered. | |
| Duty cycle andapplication cyclicity | Primary target of micro drives are quadratic torque and simple constant torque applications, so attention needs to be paid when using them in cyclic applications. | When used in demanding constant torque applications, the drive should be oversized in order to maintain lifetime expectation. | |
| Motor cabling | Long motor cabling requires special consideration because high frequency common mode current causes drives to overheat. | Drive derating, external output choke or EMC need to be considered. | |
| Multi-motor systems | When several motors are powered by one drive, the common mode current increases and therefore current also increases (because of parallel connection of motor windings). | The same dimensioning criteria as for single motor drives do not apply to multi-motor applications. | |
| Supply network quality | The drive usually has a limited amount of input reactance and therefore unstable power supply causes stress for the drive’s input bridge. | Input choke enhances the reliability of the drive. | |
| Harsh environment | The drive is constantly or occasionally exposed to dust and/or humidity or even splashing or spraying water. | IP66/67 variant needs to be selected. Also, proper filtering and preventing hot air circulation inside the cabinet are useful methods. |
Open the ABB micro drives dimensioning guide here
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