VFD’s (Variable Frequency Drives are a great way to save energy on paint booths and prep stations. Depending on your type of paint booth or finishing station, you may only have one motor that can be fit with a VFD or if you have a heated paint booth or spray area, two VFD’s is possible which can lend itself to some other energy saving features.
Traditional motor start-up on your paint booth or prep station mechanicals causes a spike in power draw. Most utility companies charge a service factor and rate the body shop according to the highest possible power draw in order to protect the overall electrical grid for the area.
For example: If a motor on your paint booth is rated for 25-30 Amps of running power, the motor draw may spike to over 100 Amps momentarily as the turbines wind up from a standstill. After a few seconds, the power draw levels out, but the damage has been done. The body shop will now be charged according to the “spike” rate, not the lower running rate.
With the use of VFD’s (Variable Frequency Drives) on your paint booth, motors are gradually started in order to get the exhaust and air makeup turbines spinning. Each VFD drive continues to increase each motor’s speed until the proper amperage is reached. This eliminates the spike in power and can save 30% or more on electrical usage. The use of VFD’s also gives the user the ability to speed-up or slow down the fan RPM which gives them great control of the cabin pressure. Maintaining proper pressure when painting in the workspace is key to not only providing the proper airflow and evacuation of overspray, but also to producing a clean paint job. Fast evacuation of overspray and fast airflow aid in flash speeds and better application while keeping pressure slightly positive will keep the work environment clean.
There are also new smart control panels on the paint booth market today that can give you some additional functions that can further increase your energy savings.
First, a new smart control panel or PLC should allow for the VFD drives to automatically maintain pressure inside the spray area by adjusting turbine speeds accordingly. This eliminates wasting power and airflow by always running the system at full power and then simply choking the airflow with a flap or damper. It also takes the back and forth out of the painter’s work day when trying to set good pressure in the paint booth. The system will automatically realize when filters are getting clogged and add power to the fans in order to compensate.
Second, a new paint booth control panel should give you “standby” or “economy mode” where the VFD drives will drop all processes to idle when the spray gun is not in use. This ensures that the system runs at full power only when the painter is spraying and that it idles whenever the painter is away. Countless electrical and fuel dollars are wasted in any facility when the painter is either in the mix room or is pulled away for another task while the booth is running at full power. A paint booth with economy mode can save thousands in both electrical and fuel energy usage over the course of a year.
With the combined power of VFD’s and a smart control panel, systems can save anywhere from 30-50% in electrical and fuel costs.