Power Relays

Power relays are electromechanical devices that are used to control the flow of electrical power in a circuit. They are commonly used in industrial and commercial applications to control large electrical loads, such as motors, heaters, and lighting systems.

Power relays consist of a coil, which generates a magnetic field when a current flows through it, and a set of contacts that are mechanically switched by the magnetic field. When the relay coil is energised, the contacts close, allowing current to flow through the relay and to the load. When the relay coil is de-energised, the contacts open, breaking the circuit and stopping the flow of current. There are multiple benefits and advantages of using power relays**:**

1. Control High Power with Low Voltage: Power relays allow you to control high power loads with a low voltage signal, making them ideal for integrating with control systems that operate at lower voltages. For example, a 24V DC relay can be used to control a high power motor.
2. Electrical Isolation: Power relays provide electrical isolation between the control circuit and the load circuit. This is crucial for protecting sensitive control electronics from high voltage spikes and ensuring safe operation.
3. Versatility: Most power relays can be tailored to meet specific application requirements. They also come in both AC power relay and DC power relay variants.
4. Durability and Reliability: Power relay switches are designed to handle large electrical loads and harsh conditions, making them highly durable and reliable.
5. Additional Features: Many power relays include features such as time delays, which can help prevent inrush currents, and surge suppression, which protects against voltage spikes. This enhances the relay's protective capabilities and extends the lifespan of connected equipment.
6. Flexibility in Application: Both high power relay and low power relay can be used in a wide range of applications, from industrial automation to commercial lighting systems, making them a versatile choice for various power management needs.

Common Variations & Configurations of Power Relays

Power relay switches are available in a variety of configurations, including single-pole, double-pole, and three-pole versions. They may also include auxiliary contacts, which can be used to monitor the status of the relay or to control other devices in the circuit.

Additionally, power relays may have features such as time delays or surge suppression to provide additional protection and control. There are various configurations available**:**

1. Coil Voltage: Power relays can be designed for different coil voltages. The coil voltage determines the control voltage needed to activate the relay. For example, a 24V DC relay is commonly used in control systems operating on a 24V DC supply.
2. Coil Power: The power consumption of the relay's coil is an important factor, especially in battery-operated applications. Low power relays are designed to consume minimal energy, making them suitable for energy-efficient designs.
3. AC/DC: Power relays can operate on both AC and DC currents, with specific relays designed for each type. AC power relays are typically used in applications involving alternating current, while DC power relays are used for direct current applications.
4. Switching Current: The switching current capacity of a power relay indicates the maximum current that the relay can handle. High power relays are capable of switching high currents, making them ideal for heavy-duty applications such as industrial machinery and high-power lighting systems.
5. Contact Configuration: Power relays come in various contact configurations, including:
   • Single-Pole Single Throw (SPST): A simple on/off switch with one input and one output.
   • Single-Pole Double Throw (SPDT): Allows switching between two outputs with one input.
   • Double-Pole Single Throw (DPST): Two separate switches operated by a single actuator.
   • Double-Pole Double Throw (DPDT): Two SPDT switches controlled by a single actuator, enabling more complex switching operations.
   • Three-Pole: Used in applications requiring the control of three separate circuits simultaneously.
6. Mounting Type: They can be mounted in various ways depending on the application. Common mounting types include:
   • DIN Rail Mounting: Used in industrial control panels for easy installation and maintenance.
   • PCB Mounting: Designed to be soldered onto printed circuit boards for integration into electronic systems.
   • Panel Mounting: Used in control panels and enclosures, providing a secure and accessible mounting solution.
7. Additional Features: Power relays may come with additional features to enhance their functionality and protection, such as:
   • Time Delays: Provide a delay before the relay activates or deactivates, useful in applications requiring timed operations.
   • Surge Suppression: Protects the relay and connected equipment from voltage spikes, ensuring reliable operation and longevity.

Applications for Power Relays

Power relays are used in a wide range of applications where electrical power needs to be controlled. Some common examples of applications where power relays are used include:

• Motor Control: Power relays are used to control the operation of electric motors in various industrial and commercial applications, such as pumps, conveyors, and HVAC systems.
• Lighting Control: Control lighting systems, such as streetlights, outdoor lighting, and indoor lighting in commercial or industrial buildings.
• Heating and Cooling Systems: Aside from industrial usage, power relay switches can be used to control the operation of heaters and cooling systems, such as air conditioners and refrigeration units.
• Power Distribution: Power relay switches like high power relay switches are also used to switch power between different parts of an electrical system, such as between a main power source and a backup power source.
• Power Factor Correction: Power relays are used to correct the power factor in electrical systems, which helps to improve the efficiency of the system.
• Uninterruptible Supplies (UPS): In UPS systems, power relays are used to switch between different power sources, such as between a battery backup and a main power source.
• Security systems: Power relays are used in security systems to control the operation of various devices, such as door locks, alarms, and cameras.

These are just a few examples of the many applications where power relays are used. As one of the essential components in many electrical systems, power relays ensure safe and efficient operation of these systems. Hence, it’s also important to keep the relays well-maintained to prevent issues and extend their lifespan.

How to Order Power Relays from RS?

RS is a trusted supplier and distributor of high-quality low or high power DC and AC power relays from top brands like RS PRO, Finder, Omron, TE Connectivity and more. When ordering power relays from RS, you can choose between online or offline purchasing.

Online Orders

• Approved Business Account Customers: Enjoy free delivery on power relay switch orders over $40 (excluding GST). For orders under $40, a S$10 delivery charge applies.
• Private Accounts and Guest Customers: Free delivery for power relay orders over $80 (excluding GST). For orders under $80, a $12.95 delivery charge applies.

Offline Orders (Telephone or Email)

To place a power relay switch order offline, you can also contact RS Australia via 1300 656 636 (telephone) / supportAU@rs.rsgroup.com (email).

• Approved RS Business Account Customers: Free delivery on power relay orders over $80 (excluding GST). A $12.95 delivery charge applies for orders under $80.
• Private Accounts and Guest Customers: Free delivery for power relay orders over $80 (excluding GST). For orders under $80, a $19.95 delivery charge applies.

Business Account Customers are defined by having a valid Australian Business Number (ABN) registration number or an RS credit account. If you are not an approved RS Business Account holder, you can apply here.

Delivery Information for Australia

Next Working Day Delivery

• Place your order before 5 pm AEST Monday - Friday for next working day delivery of locally stocked power relay switches.
• Orders placed after 5 pm on Friday will be delivered on Tuesday.

Exclusions

• Global Stock and Extended Range Products.
• Hazardous products, items over 20 kilogrammes, or longer than 1.5 metres.
• Some regional areas may have additional lead time restrictions.
• Non-core products may have longer lead times.

Same Day Delivery (Sydney Metro Orders)

• Available for power relay orders placed Monday - Friday before 11:45 am AEST.
• Available to all RS Business Account holders, excluding Extended Range and Calibrated Products.

Relevant restrictions and charges apply.

Consolidated Delivery

Combine multiple power relay switch orders into a single delivery to reduce handling.

Same Day Collection

Available at our Sydney Click & Collect Counter, open Monday to Friday from 8 am – 2 pm. Call or order online and request to pick up your power relay parcel from our Sydney branch.