The compact Windjammer brushless dcblowers from AMETEK Technical & Industrial Products (Kent, OH, U.S.; www.ametektechnicalproducts.com) offer low-voltage solutions for medical and commercial end-uses. Previously available under the Minijammer brand, those 12/24-V-dc compact blowers are 5 in. (127 mm) in diam and 3 in. (76 mm) long. “They provide a technical solution for appliance OEMs who are challenged with a design or application that requires compact size, high performance, and various features and benefits of variable-speed brushless dc (BLDC) motor technology,” says Jeffrey L. Anzevino, technical sales and applications manager. Typical applications include medical devices, such as airbeds, laser-therapy cooling, and lab equipment, high-volume copiers, digital printers, and fuel cells.

According to Anzevino, using the BLDC motor technology allows the blowers to enjoy virtually maintenance-free operation over a long service lifetime. Unlike brushed dc motors, “there are no carbon brushes to wear through the mechanical contact to a commutator,” Anzevino says. Instead, the BLDC motor is commutated via an electronic control module, which senses the magnetic pole of the motor’s rotor through three Hall-effect sensors. “The controller’s motor-control chip then analyzes these data and determines the correct motor phase to energize with current flow. This process continues to happen and change current flow through the appropriate winding to allow for continued rotation of the motor shaft,” explains Anzevino.

Other features in the blower design also contribute to the long operating life of the blowers, says Anzevino. Those include high-temperature bearing greases, improved contact bearing seals, and stainless-steel components within the fan chamber.

For additional design flexibility, the compact Windjammer blowers allow users to specify either internal or external commutation drive electronics. The advantage of having the internal electronic controller module as part of the blower package is that it does not increase the size of the blowers, thus saving system space. “It also alleviates the need for additional cables and contacts that would be required for a controller module located elsewhere within the OEM’s system,” Anzevino says.

But in some cases, such as in applications where the blower’s working air needs to be kept cool, having a remote electronic control module could be a plus. “The electronic controller does generate some heat through the power switches (MOSFETS), and that heat dissipation may be more desirable and easier for the OEM to manage if it is removed from the area of the blower component.” In such a case, the blower allows for the required connection to a three-phase, brushless dc electronics control module that is remotely located. In addition, other options are available to meet particular custom application requirements.

With the electronic controller, Anzevino says, the user controls the blower’s motor speed with either a mechanical adjustment of an on-board potentiometer or via a logic level dc signal connection that equates to a 0–4-V-dc speed command input (supplied by the OEM’s system). The latter allows the OEM to have a closed-loop system where the blower can be commanded to change speed, so as to match a desired performance point within the OEM’s system. “An example of this is a closed-loop system by the OEM that incorporates a pressure transducer to monitor the air pressure at a given point in their system. As that pressure changes from various environmental factors or end-user requirements, the OEM’s system can incorporate additional circuitry that will then automatically adjust the speed command signal to AMETEK’s blower,” says Anzevino.

The compact blowers can achieve output pressure up to 25-in. H2O and flow rates up to 45 cfm, depending on the model. The blower’s maximum power requirement is 155 W, depending both on the model and the application’s load point.

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