Industrial Inverters can be used in the home and are often seen fitted to Myford and other metal Lathes, Wood Lathes, Drill stands, small Industrial machine tools and many other pieces of "hobby workshop" equipment. These notes are intended to help the user complete the installation, free from problems and risk as far as possible.
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The motor needs to be suitable for 240V 3 phase input, see note (a) and for the application. Refer to the motor listings on this site for power and torque outputs and current ratings. Machine tools, pumps and fans are all simple applications for Inverters, as long as there is nothing else connected to the motor circuit. If you are in doubt about the application contact us. If the motor is 415V and cannot be changed to 240V, it can still be used - see note (b) below.
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The motor cable will be limited for length, usually about 30mtrs and is detailed in the manufacturer’s documentation. The cable should be screened and securely earth the motor to the Inverter via the same cable. Search for ‘power cable’ on this site.
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Interference with Other Equipment - The drives should include what are known as EMC Filters to the ‘First Environment’, see note (c) below. Many Drive Manufacturers include filters in the basic product to the 1st or 2nd Environment. External additional filters are sometimes necessary for some manufacturers to comply with the requirements of the 1st Environment.
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To comply with UK regulations, the motor and Inverter need to be permanantly earthed and not categorised as a ‘Portable Appliance’. This is because it is Industrial equipment and there may be Voltage present on the supply after disconnection for longer than is permitted for a ‘Portable Appliance’. For this reason you are advised to use shrouded plugs and sockets.
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The supply needs to be suitable for the current rating of the drive. Refer to the drive details listed on this site.
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Consideration must be given to the supply, if you have an Earth Leakage Circuit Breaker fitted. The Inverter is likely to cause this to trip, see note (d).
Notes:
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240V Input. Usually this means the motor terminal box links are arranged in the three abreast ‘Delta’ position. Motor performance will be exactly the same as if it had a 415V Inverter fitted.
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240V onto 415V Motors. This just means you must set the ‘Base Frequency’ to 29Hz in place of the default 50Hz. The motor will run with normal full load torque (as if it has a 415V Inverter fitted) as far as 58% speed, and then the torque available will progressively reduce to 58Hz or about 120% of its plated speed. The Inverter must be rated to suit the flc of the motor and not it’s kW.
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EMC Environment Designations: First Environment (Domestic) "The First Environment includes domestic premises. It also includes an installation directly connected without intermediate transformer to a low-voltage power supply network which supplies buildings used for domestic purposes." Second Environment (Industrial) "Second Environment includes all installations other than those directly connected to a low-voltage power supply network which supplies buildings used for domestic purposes."
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The EMC filters have small capacitors connected to earth, as part of the filtering circuit. When powering up, the small pulse of current into the capacitors will trip a standard ELCB. Inverters are available without EMC Filters or with low earth leakage for installations requiring ELCB protection. Contact us if you need this type of drive. Special ELCB's are available with preset or adjustable leakage levels to work with Inverters, but the detection level is generally higher than is required for personnel protection.
This information is made public and is given in good faith to improve the knowledge of the reader and help the trouble free use of Inverter Drive Products. The requirements are based on good practice, UK Installation regulations and European laws. It is up to you to decide how to comply. If you have any doubts about your installation, contact a competent and qualified Electrician. Guidance and Installation notes written by the manufacturers are included with the products. We accept no responsibility for your use or installation of the Inverters or other products offered by our Company.