Hi. It was one productive quick class for understanding fan curves. Questions: at 5:25, you said that turning down the SCR would lead us to get a reduced efficiency. Could you possibly elaborate for me the correlations between SCR going down and decrease in the efficiency?
The podcast is talking about a permanent split capacitor (PSC) motor with a silicon-controlled rectifier (SCR) speed control. These speed controls reduce the motor speed by chopping and notching the AC-sine wave power. This slows the motor but it also reduces the electrical efficiency of the motor. It can also cause these motors to run hotter and possibly produce low frequency humming noises. PSC motors have a typically efficiency range of 20-60% and the efficiency drops as speeds are reduced with this type of speed control. For this reason, I recommend selecting PSC motors in the top 75% of their fan curve.
Hi. It was one productive quick class for understanding fan curves. Questions: at 5:25, you said that turning down the SCR would lead us to get a reduced efficiency. Could you possibly elaborate for me the correlations between SCR going down and decrease in the efficiency?
The podcast is talking about a permanent split capacitor (PSC) motor with a silicon-controlled rectifier (SCR) speed control. These speed controls reduce the motor speed by chopping and notching the AC-sine wave power. This slows the motor but it also reduces the electrical efficiency of the motor. It can also cause these motors to run hotter and possibly produce low frequency humming noises. PSC motors have a typically efficiency range of 20-60% and the efficiency drops as speeds are reduced with this type of speed control. For this reason, I recommend selecting PSC motors in the top 75% of their fan curve.
What is vacuum - temperature rise curve?