White paper on using PLC with Vibratory Bowl Feeders
Whenever, a vibratory bowl feeder is used in a an assembly machine or else along with more sophisticated equipment, a PLC is required to be used along with the same. This is not required when a vibratory bowl feeder is used for feeding of components to a press or to a centerless grinding machine.
When used along with a PLC, it is observed many times, that the speed of the vibratory bowl feeder varies during operation or else there might be jerky movement. This happens due to radio frequency (RF) interference or electrical noise between the coils of the vibratory bowl feeder or the vibrator controller and the PLC and other electrical items in the Electrical Panel. One way to eliminate this is to use proper RF filters, which may not be easy to procure and use. Another way is to use an isolation transformer to isolate the supply given to the vibrators from the panel.
An isolation transformer is a transformer used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source, usually for safety reasons. Isolation transformers provide galvanic isolation and are used to protect against electric shock, to suppress electrical noise in sensitive devices, or to transfer power between two circuits which must not be connected. A transformer for isolation is often built with special insulation between primary and secondary, and is specified to withstand a high voltage between windings.
Isolation transformers block transmission of the DC component in signals from one circuit to the other, but allow AC components in signals to pass. Transformers that have a ratio of 1 to 1 between the primary and secondary windings are often used to protect secondary circuits and individuals from electrical shocks between energized conductors and earth ground. Suitably designed isolation transformers block interference caused by ground loops. Isolation transformers with electrostatic shields are used for power supplies for sensitive equipment such as computers, medical devices, or laboratory instruments. Similarly, they can be used for vibratory bowl feeders.
Thus, the major advantages of using an isolation transformer are –
- Isolation in different circuits can be substituted by isolation transformers. With 1:1 ratio, isolation transformers can separate the primary and secondary windings.
- Isolation transformers facilitate direct current power isolation. In case of telephone lines, where amplifiers are required at various intervals, it is isolation transformers that carry out the separation of direct current components from the signal to control every amplifier on the line.
- Isolation transformers prevent the risk of electric shock by uniting a vessel to the electric power source. They facilitate separation of the person from the resource in a manner that the electric wirings do not touch the power line directly.
- Without isolation in electronics testing and servicing, touching a live part of the circuit can prove to be dangerous. Thus, 1:1 ratio transformers are used for isolation in order to provide safety. Isolation transformers have therefore proven to be an excellent option for gadgets that use electricity.
- All kind of noise and sound that is created by connecting the signal of the audio amplifier to the speaker output circuit is reduced with the help of isolation transformers.
- Isolation transformers separate the amount generated by a radio frequency on large devices of the circuit from the transmitter line. They facilitate the connection of the amount produced by the radio frequency amplifier to the transmitted signals and direct it towards the antenna.
.Hence, it is recommended that a 3 Phase input supply be used in the panel, a 2 Phase to 1 Phase isolating transformer of the correct rating be used and one phase be isolated and taken to the vibrator controllers. This is an easy way to ensure that the RF interference and electrical noise between the vibrator and the panel be eliminated. This will not only ensure smooth functioning of the vibrators but provide good life for the vibrator controllers and coil.