The 90-370 relay is a popular choice for HVAC technicians and electricians. This relay is used to control the operation of the compressor in air conditioning and refrigeration systems. Its wiring diagram can be a bit confusing for those who are just starting out in the field. In this article, we will take a closer look at the 90-370 relay wiring diagram and provide a step-by-step guide on how to wire it.
What is a 90-370 Relay?
The 90-370 relay is a type of potential relay that is commonly used in HVAC and refrigeration systems. It is a switching device that uses an electromagnet to switch contacts. The contacts are used to control the operation of the compressor. The 90-370 relay is designed to provide reliable and accurate control of the compressor in a variety of operating conditions.
How Does a 90-370 Relay Work?
The 90-370 relay has three terminals: start, run, and common. The start terminal is connected to the start winding of the compressor motor. The run terminal is connected to the run winding of the compressor motor. The common terminal is connected to the power source and the overload protector. When the compressor is started, the start winding is energized, and the relay contacts close. This connects the start winding to the run winding, and the compressor motor starts running. Once the compressor motor reaches its operating speed, the start winding is de-energized, and the contacts of the relay switch back to their original position.
The 90-370 relay is a potential relay, which means that it uses a capacitor to energize the start winding. The capacitor provides an extra boost of power to the start winding, which helps the compressor motor start more easily. The relay contacts are designed to handle higher voltages and currents than the capacitor, which helps to protect the capacitor from damage.
Wiring a 90-370 Relay
Wiring a 90-370 relay can be a bit tricky, especially for those who are just starting out in the field. Here is a step-by-step guide on how to wire a 90-370 relay:
Step 1: Turn Off the Power
Before you start wiring the 90-370 relay, make sure that the power to the system is turned off. This will help to prevent any electrical shocks or accidents from occurring while you are working on the system.
Step 2: Locate the Relay
The first step in wiring a 90-370 relay is to locate the relay in the system. The relay is usually located near the compressor or on the compressor itself. It will have three terminals: start, run, and common.
Step 3: Connect the Power
The common terminal of the relay should be connected to the power source and the overload protector. The overload protector is a safety device that helps to prevent the compressor motor from overheating. The power source is usually a 240V AC power supply.
Step 4: Connect the Start Winding
The start terminal of the relay should be connected to the start winding of the compressor motor. The start winding is usually the smaller of the two windings on the compressor motor. It is designed to provide an extra boost of power to the motor when it is starting.
Step 5: Connect the Run Winding
The run terminal of the relay should be connected to the run winding of the compressor motor. The run winding is usually the larger of the two windings on the compressor motor. It is designed to keep the compressor motor running once it has started.
FAQ
What is a potential relay?
A potential relay is a type of relay that is used to control the operation of a motor. It uses a capacitor to energize the start winding of the motor, which provides an extra boost of power to help the motor start more easily. The relay contacts are designed to handle higher voltages and currents than the capacitor, which helps to protect the capacitor from damage.
What is the difference between a potential relay and a current relay?
A current relay is a type of relay that is used to control the operation of a motor. It uses the current flow through the start winding to energize the relay contacts. The contacts are designed to handle the current flow through the start winding. A potential relay uses a capacitor to energize the start winding, which provides an extra boost of power to help the motor start more easily. The contacts are designed to handle higher voltages and currents than the capacitor, which helps to protect the capacitor from damage.
Can I wire a 90-370 relay myself?
If you have some experience with wiring electrical devices, you can wire a 90-370 relay yourself. However, if you are not familiar with electrical wiring, it is recommended that you hire a professional to wire the relay for you. This will help to ensure that the system is wired correctly and that there are no safety hazards.
What is the purpose of the overload protector?
The overload protector is a safety device that is designed to protect the compressor motor from overheating. If the current flowing through the motor exceeds a certain level, the overload protector will trip and disconnect the motor from the power source. This helps to prevent damage to the motor and other components in the system.
| Terminals | Description |
|---|---|
| Common | Connected to the power source and the overload protector |
| Start | Connected to the start winding of the compressor motor |
| Run | Connected to the run winding of the compressor motor |
In conclusion, wiring a 90-370 relay can be a bit confusing, especially for those who are new to the field. However, with this step-by-step guide, you should be able to wire a 90-370 relay with ease. Remember to always turn off the power before working on any electrical system, and if you are not familiar with electrical wiring, it is recommended that you hire a professional to do the job for you.
