How To Connect The Motor Start Capacitors Of An Electric Motor

This article provides instructions on the installation and connection of electric motor start capacitors for electric motor starting capacitors designed to start and run electric motors such as AC compressors, heat pump compressors, fan motors, and air wiring for difficult starting. How to do it. Air conditioner compressor motor, fan motor. Run air conditioners, heat pumps, refrigerator or freezer compressors, or other electric motors (such as well pumps).
This series of electric motor capacitor articles will help you get started and run electric motor starters used in a variety of electric motors in or in buildings such as air conditioner compressors, fan motors, some well pumps and some heating Learn about selection, installation, testing and use of capacitors. device.

How to install and connect air conditioner compressor, blower motor or fan motor start capacitor

Whether you’re simply installing the replacement motor start capacitors, or installing a “hard-starting” capacitor to try and run a noisy electric motor, the steps for capacitor selection and installation are the same.
A “hard start” motor capacitor is a capacitor that gives a little extra boost or torque to make the motor spin.
If an electric motor, such as an A/C motor, is having trouble starting, it is common for a service technician to try a new starting capacitor. Because the steps are quick, easy and inexpensive.
It also makes sense that most electrical problems in air conditioning systems are in the compressor and the overloaded relay switch or motor.
However, keep in mind that the underlying problem may be a more serious malfunction within the engine itself. For example, broken starting or engine windings, or failure of engine bearings. With a single-phase compressor (a typical residential air conditioner), an ohmmeter can tell if an air conditioner compressor is bad. I will explain the steps separately
Before replacing a new starting capacitor or running capacitor, you need to know which motor terminals will be used.
Note that in the capacitor test, the letters S, C, and R are used to identify the normal terminals to which the operating/running capacitors are connected. please. In many systems, these terminals are already marked so that you can correctly connect the three leads of the starting / running capacitor.

• S = start of wire conductor
• R = Run wire connector
• C = common conductor

But what if there are no signs?
CAUTION: Do not connect the starting or running capacitors to the motor before the motor capacitor terminals are correctly identified. The engine may be damaged.

How to identify the starting terminals and common capacitors in an electric motor

The terminals of the electric motor should be marked as S – R – and C (start, running, general).
But what if these marks are lost? Before you can figure out how to connect a replacement starting or starting capacitor to your motor, you need to know the motor’s terminals.
With the simple steps outlined here, you can easily and quickly learn the terminal. A partial power electric motor must exhibit different electrical resistances between its three terminals (starting, running and common).

• First, arbitrarily name the three terminals A-B-C, then measure the resistance between each potential pair and write down the results.
• Test the resistance between each pair by serially testing each pair of two of the motor’s three electrical terminals using a VOM in an OHMS setup.
• Before we know which of the three stations are actually Common, Start, and Run, we arbitrarily call them A, B, and C.
• By comparing the resistances between each of these three pairs, we can determine which one is C or common and which one is S – Start and R – Run.

Add the resistance measurements to find the terminals with the highest resistance, as shown in the table above.

For Example

• Terminal A has two measures of resistance. A B and A C have 6 ohms and 3 ohms. Adding them gives 9.
• Terminal B has two resistance measurements. A B and B C are 6 ohms and 8 ohms. Adding them gives 14.
• Terminal C has two measurements of resistance. A and BC are 4 ohms and 8 ohms. Adding them gives 11.
• We can see that the terminal with the lowest total resistance (9) is A. Therefore, name it common terminal C.
• We can see that the terminal with the highest total resistance (14) is B. So label this with S on the starting terminal where the starting capacitor is connected.
• Label the operating terminal to which the operating capacitor is connected as R, because the terminal with total resistance (11) between the other two is C.

How to determine the engine speed

By the way, most electric motors have a data label that indicates the rotational speed (RPM) of the motor but remember that it is the number of rotating coils that determines the rotational speed of the motor.
A visual inspection of the engine or its internal parts shows that the engine is running at 3450 rpm (“nominal” 3600 rpm) with two coils. Four coils represent a 1725 rpm engine.

Simple Relay Instructions and Solid Start Capacitor Wiring – Example 1

Solid starter relays and capacitors can be installed such as the Starter Pow-R-Pak. In the original system without any changes in wiring. Quotation of the company’s relay and solid start capacitor part number SPP-5.

Simple Relay Instructions and Solid Start Capacitor Wiring – Example 2

Below is an example of a capacitor installation procedure for adding motor start capacitors to an air conditioning compressor motor. This is an excerpt from the product packaging for relays and starting capacitors intended for use in the refrigerator or freezer. A similar starter condenser can also be used for air conditioning compressors.

• Unplug the power cord from the outlet. In other words, make absolutely sure that the power to the equipment being serviced is turned off.
• Leave the old overload protector in place and remove the old starting relay.
• Push the wire from the single-pin end to the “start” terminal of the A/C compressor.
• Push the other wire with the pin end into the “running” terminal on the A/C compressor.
• Connect the wire from the old starting relay to the spade terminal on the “running” wire (insulated sleeve).
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