Q: I have an application where I need consistent airflow to cool some metal components that I manufacture. The fans I use often slow down over time thus decreasing airflow. This lower airflow adversely affects my components since it won't provide the cooling I need, and I have to scrap the metal components and order new fans while dealing with down time. What kind of alarms or protection options do you offer for your fan products to eliminate this issue for me?
A: Our fan products do feature a variety of alarms and protection functions to help minimize downtime. We offer fans with impedance protection, overheat protection, low speed alarms as well as stall alarms in both electronic or contact type to fit your needs. Impedance protection and overheat protection prevents damage to the fan motor while the speed alarms ensures the performance you expect and allows planning of replacements more efficiently.
For your low fan speed issue, we would suggest looking at our fans with either low speed, stall alarms, or pulse sensor output. Fans with low speed alarms outputs an alarm signal when the fan speed drops to a certain level due to either end of life or ingress of foreign objects. Fans with stall alarms output an alarm signal when the cooling fan stops. Pulse sensor output type fans output digital square waveform pulse signals at a certain frequency (2 pulses per revolution of the fan motor). By using a pulse sensor output, the user can customize the type of alert according to their specific preference. The fan that needs to be replaced is also quickly identified with these alarms. These types of alarm are offered on MRS and MRE series AC axial flow fans, MDS and MDA series DC axial flow fans, MBD series DC centrifugal blowers and MFD series DC cross flow fans.
We also offer fans with overheat protection. If a fan in operation locks due to overload, ambient temperature rising too rapidly, or the input current draw rises abruptly, the fan's temperature will rise abruptly. If the fan is left in this state, the performance of the insulation within the fan may deteriorate, reducing its life. In extreme cases, it might even cause a fire. To prevent this, our fans which are recognized by UL and CSA standards and conform to EN and IEC standards offer built-in overheat protection. Depending on the type of the fan, either thermal protection or impedance protection is offered.
Impedance protection is offered on the MU and MB series axial flow fans. These fans have higher impedance in the fan windings so even if the fan locks, the typical increase in current draw is minimized and as a result also limits the temperature rise at a certain level.
Thermal protection is offered on MRS series axial flow fans, MB series centrifugal blowers, as well as the MF series cross flow fans. If the temperature of the fan rises above a certain level, the thermal protection cuts off power to the fan motor therefore allows it to cool down. When it cools beyond a certain level, it will allow the fan to operate again. Inside our thermal protector, we use a bimetal contact with different heat properties in the power circuit. As the bimetal contact senses an abnormal rise in temperature, it will bend until power is disconnected from the fan motor windings. Please see an image below.
With our DC fans, we offer a "burnout prevention circuit" which cuts power to the motor windings or limits the current when the fan motor is locked.
For more information about our fan products, please visit the following pages:
WEB FAN OVERVIEW: http://www.orientalmotor.com/products/a ... index.html
CATALOG OVERVIEW: http://www.orientalmotor.com/products/p ... erview.pdf
FAN ALARM SPECIFICATIONS: http://www.orientalmotor.com/products/p ... _specs.pdf
TECHNICAL REFERENCE: http://www.orientalmotor.com/products/p ... roduct.pdf
TYPICAL FAN APPLICATIONS: http://www.orientalmotor.com/applicatio ... ml#cooling (scroll all the way down)
If you have any questions, please contact our knowledgeable technical support group to discuss your application.
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