Motors, Capacitors & Starting Components

In residential and light commercial HVAC, we work primarily with PSC (permanent split capacitor) motors. However, it is good to be aware of some other types. PSC (Permanent Split Capacitor) A common medium torque single phase motor with a run capacitor always in the circuit. This type makes up the majority of HVAC motors (condenser […]

Knowing how to combine capacitors in series and parallel properly is a great practical field skill to employ when you need to get a customer up and running, but you don’t have the exact size. Increasing in size is easy. Just connect in parallel and add the two sizes together. For example, if you needed […]

Now is the part where we get specific about start capacitors and inrush. If you haven’t read the first three parts, please do so before reading this one, or it may not make sense. (You can find Part #1, Part #2, and Part #3 at these links.) I’m going to come out and say it […]

Before we get into the parts that will ruffle some feathers, let’s talk a bit about what a “Start” capacitor is and what it does. First, let’s review that both start and run capacitors connect between the leg of power opposite of compressor common and the start winding. Even though it seems like a run capacitor […]

Thought Experiment #3 – The Start Winding Has No “Inrush” with a run capacitor only  The name “start winding” is an antiquated term for the single-phase residential industry. It came from the days when CSIR (capacitor start, induction run) motors were still used commonly. In a CSIR motor, the start relay removes the start winding […]

This series of articles is one of those that will bug a lot of people because it will go against a lot of what you’ve been told about compressors, start capacitors, and inrush current. For that reason, I want you to work through a few thought experiments first and maybe even stop and try it […]

This tip was created by Jason Pinzak and originally posted on the HVAC Technician’s Facebook group. It is reposted here with permission from Jason. Thanks! Contactors are useful in commercial and industrial applications, particularly for controlling large lighting loads and motors. One of their hallmarks is reliability. However, like any other device, they are not […]

Can a single-phase motor run backward when start and run are swapped? The answer is (generally) yes. Is the motor designed to run backward by simply swapping run and start? The answer is (generally) no, with a few notable exceptions. Before we jump in, this article has two purposes. #1 – it helps you understand […]

In a previous article, we covered the standard way to check capacitors under load. I am now going to give you an even easier test. A properly functioning PSC (permanent split capacitor) or CSCR (capacitor start capacitor run) motor should have a power factor of very close to 1 if they have a properly sized […]