We have gained a lot of experience working with electric powder coating ovens including new builds, upgrades and retrofit controls. If you are looking to develop your powder coating process we have the knowledge and products to assist you. Here we share some of the commonly asked questions, problems and solutions when working with electric powder coating ovens.

How Do Electric Powder Coating Ovens Work?

Electric powder coating ovens come in various sizes to suit the type of product being loaded and the available electrical supply. All ovens will require a temperature controller to maintain a stable internal temperature, average setpoints are in the range 160-200C. Other electrical parts typically required would be solid state relays, elements and a temperature probe/thermocouple. Along with this are some important safety components including circuit breakers or fuses, isolator and overtemperature device.

The elements can be configured for single or three phase supplies. The number of elements will define the total KW output of the oven. Common sizes we see are in the 7-12KW range. Typically composed of 3-6 individual elements, with circulation fans.

The principle of operation is simple, turn on the oven. The temperature controller will read the internal temperature and continue to apply power to the elements until the setpoint is reached. Timer functions can be used to turn the elements off at the end of a cycle. We recommend our N1030T model as it contains a simple built in timer which can be adjusted easily. A typical cycle might work as follows:

• Turn on the oven
• Wait for setpoint to be reached
• Load oven with parts
• Timer beings (e.g. 10 minutes @ 160C)
• Timer ends, oven will cool down

Figure 1 - Electric Powder Coating Oven For Automotive Parts

Considerations When Building Electric Powder Coating Oven

There are some important design considerations which can save downtime in future and ensure your oven runs optimally:

• Siting electrical controls - although some ovens have built in controls it is is important to consider the temperatures involved and the nature of powder in the air. We prefer to see a dedicated electrical control panel mounted separately to the oven. This gives good access to the control system but helps to avoid some of the issues associated with heat and fine particles
• Choice of components - we sell Novus controllers with a 3 Year Warranty. There are many temperature controller suppliers on the market. Our main recommendation here is to use an established brand which meets CE or other internationally recognised standard. A cheap unbranded controller is not going to give many years of service and may also lead to more serious issues. The investment here is small our N1030T is under £50.00+VAT
• Solid state relays - SSRs are an important part of the process as they are switched by the controller to apply power to the elements. This switching can occur very quickly to ensure the temperature does not overshoot. PID temperature control is covered in depth elsewhere but the role of the SSR should not be neglected. SSRs generate heat and are the number one cause of failure on the powder coating ovens we see. If the SSRs have been appropriately rated, installed and ventilated you can expect very few issues. Read on to see some of our tips for a successful oven build
• Rating of cables and components - it is crucial to consider the cable type and current rating is appropriate. This is true for all of the internal connections as well as the main supply to the oven. The use of MCBs and fuses will only be effective if some basic calculations based on the element sizes have been carried out
• Think about safety - there are some basic questions which can avoid potential dangers such as: Are all materials suitable for the temperature involved with a margin of safety? What happens if the temperature control fails and the oven overheats? What happens if one element or SSR fails? We also recommend the use of appropriate ventilation to deal with any fumes generated

Figure 2 - Novus N1030T And Parts For Powder Coating Ovens

Tips For Building Electric Powder Coating Oven

There are many mechanical design considerations when building a new oven. Here we share our best tips for electrical design which can be applied to new or old power coating ovens.

1. Build a dedicated electrical enclosure to house the temperature controller, solid state relay and other electrical components. This enclosure should have a single point of electrical isolation for the oven
2. Ensure all cables are appropriately sized for the electrical loads required and are of the correct type for the temperatures they will be exposed to
3. Choose branded components, they don't need to be high end or leading brand. But if your oven is going to be reliable you will need to make a modest investment
4. Dissipate heat from SSRs. Check they are oversized for the electrical load, mounted to a heat sink with thermal paste. Running a 40A SSR at full load with no heat sink is a recipe for disaster
5. Fit an overtemperature device. This can be a mechanical or electrical device that will interrupt the supply to the elements in the event of a maximum temperature being reached. This should function independently of the main temperature controller
6. Consult professionals. If you are unsure about how to wire the oven controls speak to us or find an electrician who is able to assist you. We have our own sample wiring diagrams which can be used as a starting point when planning a new build or modified controls

Figure 3 - Failed Solid State Relay

Common reasons for early failure of a solid state relay include loose terminals, improper rating, inadequate heat sink, lack of thermal paste and poor mounting. SSR failures are the number one cause of downtime on Electric Powder Coating Ovens. We recommend quality heat sinks as pictured below. 

 Figure 4 - Solid State Relays With Heat Sinks

Figure 5 - Novus N1030T Prewired Bundle Kit For Customer