Braking resistor frees up panel space

Due to the growing complexity of the industrial sector, it has become difficult for engineers to design applications which maximise space and power while ensuring that equipment is safe and reliable to use. This problem was addressed recently by the IET, which proposed changes to the Eco Design Directive being drafted as part of EU legislation. 

VSDs are being increasingly used within HVAC and pumping applications, which can cause damage to equipment through prolonged exposure to dust. To address this, the resistor is protected with an IP20 rating as standard, allowing it to be used in areas without control housings. On request, the device can be supplied with a protection rating of up to IP64.

"Better use of the available installation space can drastically affect the performance of components," commented Steve Hughes, Managing Director, REO. "We originally developed the unique mounting system for a leading drive manufacturer in the building technology, HVAC sector. However, for the past two years, the design has been under embargo.

"The launch of the BW156.9 fulfils two core needs. Firstly, components can be mounted on the panel housing the braking resistor. Secondly, this moves the potentially hot resistor away from engineers working on the panel and reduces the requirements for additional guarding," added Hughes.

"The resistors can be locally force cooled, which increases their power rating by 20%. By default, the units are rated for 900V and can be supplied with variants from 200W to 30,000W, and in resistance values from 1 to 2000R," said Hughes.

"We did face some design challenges in developing this unit," added Hughes. "The key point was ensuring that the heat from the resistor is not transferred to the mounting surface. We were able to overcome this issue by using insulated standoffs to isolate the panel from the resistor and ensure that anything mounted does not get hot."