How to use VFD control panel

 What is a VFD Control Panel?

VFD Control Panel

Variable frequency drives are an essential part of any manufacturing plant. Its continuous operation is necessary to maintain the production of the plant, How to use VFD control panel and any failure results in a chain reaction, effectively bringing the entire industry to a standstill.

 

Manufacturing plants are notorious for their harsh work environments, ranging from moisture to dirt to rust. Variable frequency drives (VFDs) may come in a protective shell, but still require protection from the elements as well as a comprehensive enclosure for all associated equipment, thus, having a VFD control panel for the plant becomes mandatory.

 

Like any other enclosure or control panel, a VFD control panel consists of an enclosure, VFD, and associated equipment such as:

 

harmonic filter.

Protection devices such as relays, circuit breakers, and stabilizers.

PLC for advanced control.

Communication devices such as switches and modems.

Temperature control devices such as anti-condensation heaters or air conditioners.

motor starters.

VFD control panels are used for four primary reasons such as:

 

1.) Power Switching and Protection

VFD panels usually host a circuit breaker or a relay which can trip in case of any fault like short-circuit, overload, etc. to the input power line

2.) Adjustable speed

Typically, the VFD panel door has a frequency control potentiometer installed to transmit a command signal to the motor according to the operator's setting. A bypass switch is located nearby to allow the motors to function in case the VFD fails.

 

3.) Protection from the environment

This is one of the major concerns for any control engineer as manufacturing units are clogged with moisture, dirt, etc., which can result in short-term and long-term problems. Chemical buildup over an open connection can usually result in reduced performance while dirt accumulation can lead to a shorter lifespan for the drive.

 

4.) Visual Control

VFD panels are not just positioned for protection against harsh conditions. Multiple field indicators are installed to obtain real-time information about the drive's power consumption, frequency, and other diagnostic information that is required of the operator. In addition, controls are embedded to allow the operator to shift the frequency or take precautionary action based on monitored values.

 

The National Electrical Manufacturers Association (NEMA) is responsible for creating different resistance levels for enclosures depending on their use.

Type 1: Drip-tight, similar to Type 1 but with additional drip shields.

Type 2: Weather resistant, protects equipment from dripping rain and rice.

Type 3R: Intended for outdoor use.

Type 4: Watertight, equipment must be protected from at least 65GPM of water.

Type 5: General purpose, provides protection against solid foreign objects such as dirt, dust, lint, etc., while shielding against water, dripping, oil spillage, and non-corrosive coolant.

The type of protection to be provided by the VFD panel should be selected about the NEMA guidelines to maintain maximum utility and safety of the instruments, and hence, minimum asset downtime.