Ningguo Kingcool Import and Export Co., Ltd supplies Air-Conditioner Parts-Relay & Overload & Delay Timer as part of a one-stop appliance parts programme covering air-conditioner, refrigerator, refrigeration, washing machine and home appliance categories. Our range centres on the small electrical components that sit between the control circuit and the compressor: start relays, thermal overload protectors and time-delay devices used in split systems, window units, commercial refrigeration and service repair work.
We combine industry and trade. Our own production is dedicated to metalized polypropylene film capacitors, and we have developed into an agent for air-conditioner and refrigerator accessories with a complete range, guaranteed quality and competitive pricing. For relay, overload and delay timer projects, that means a single supplier for the switching and protection components around the compressor, together with the capacitors, contactors, transformers and motors that share the same circuit.
What We Supply in This Category
As a Air-Conditioner Parts-Relay & Overload & Delay Timer Manufacturers, we match product configuration to the application, operating limits, interfaces and acceptance criteria defined for each project.
This category covers the components that start, protect and sequence compressor operation. A compressor cannot be connected directly to the mains: it needs a start device to bring the rotor up to speed, a thermal protector to open the circuit when winding temperature or current rises beyond a safe level, and in many circuits a delay timer to prevent short-cycling after a power interruption or thermostat cut-out.
Our current range in this family includes the Compressor Relay Starter 1/3HP and the Compressor Thermal Overload Protector. Both are stocked as service and production items, and both are supported by the wider Air-Conditioner Parts range so that a repair or assembly order can be completed from one source.
Compressor Relay Starter 1/3HP
Current-type start relay for single-phase compressors in the small fractional horsepower class. Plastic, metal and copper construction in black and copper tone, with a compact 35 x 35 x 35 mm body that fits the standard terminal cluster on small hermetic compressors.
Typical fit: window units, small split systems, beverage coolers and service replacement where the original start relay has failed open or welded closed.
Compressor Thermal Overload Protector
Bimetal thermal protector used in refrigeration, air conditioning, heating and electric motors. It opens the compressor circuit on excess temperature or current and resets automatically once the device cools, protecting the winding from sustained overload.
Typical fit: hermetic compressor protection, motor overload protection, and lead-and-wire-nut installation where a simple, direct-mounted protector is required.
Where Each Device Fits in the Circuit
Relays, overload protectors and delay timers are often grouped together because they share the same compressor terminal area, but they perform different jobs. Matching the right device to the right function avoids nuisance trips and repeat service calls.
| Device | Function | Typical Application | Key Selection Data |
|---|---|---|---|
| Start relay | Switches the start winding in during run-up | Single-phase hermetic compressors, small A/C and refrigeration | Compressor HP, terminal layout, coil voltage |
| Thermal overload protector | Opens circuit on over-temperature or over-current | Compressor winding protection, motor and lead protection | Trip temperature, current rating, mounting style |
| Delay timer | Holds off restart after power loss or cut-out | Compressor short-cycle protection, defrost sequencing | Delay period, supply voltage, contact configuration |
| Contactor / transformer | High-power switching and control supply | Larger split and packaged units, control panels | Rated current, coil voltage, auxiliary contacts |
Relays are generally used for low-power control and signal-level switching, while contactors handle high-power loads such as motor start and stop. In an air-conditioning circuit the two often appear together, which is why we keep both families in stock and can quote them as one package. See Contactor & Transformer for the higher-current side of the panel.
Materials, Ratings and Configuration Options
Relay and protector bodies combine plastic housings, metal frames and copper contacts and coils. The materials determine contact life, arc behaviour and resistance to the vibration and temperature cycling found on a compressor deck. We confirm the following configuration points before quoting:
- Compressor class — fractional horsepower rating such as 1/3HP, or the equivalent kW/BTU band of the unit.
- Coil and supply voltage — 110V, 220V or the voltage stated on the unit nameplate.
- Terminal geometry — pin spacing and orientation so the device seats correctly on the compressor terminal cluster.
- Trip characteristics — protector opening temperature and current threshold for the winding being protected.
- Delay period — the hold-off time required to prevent short-cycling after a power interruption.
- Mounting style — direct-mount on the compressor, bracket mount, or panel mount with leads.
Where a unit uses a capacitor-assisted start circuit, the relay, protector and run capacitor must be matched as a set. Our capacitor production and our Capacitor range allow us to supply the complete start circuit rather than a single component.
Application Fit Across Our Range
Relay, overload and delay timer components are used wherever a hermetic compressor or electric motor needs controlled starting and reliable protection. The table below shows how they connect to the other categories we supply.
| Application | Relay / Protector Role | Related Kingcool Range |
|---|---|---|
| Split and window A/C | Start relay and thermal protection on the compressor | Compressor, Capacitor, Contactor & Transformer |
| Commercial refrigeration | Overload protection and defrost sequencing | Defrost Timer, Thermostat, Filter Drier |
| Service and repair | Direct replacement of failed start or protection devices | Full Air-Conditioner Parts and Refrigerator Parts range |
| Motor and fan circuits | Overload protection on fan and pump motors | Indoor And Outdoor Air Conditioning Motor, Axial Fan |
Quality Control and Acceptance
Our capacitor production runs on high-precision slitting and winding equipment with testing equipment that monitors the process in real time, and the same quality discipline applies to the accessory lines we distribute. Components are checked for contact condition, terminal fit, coil continuity and mechanical integrity before packing.
For project orders we agree the acceptance basis in advance. Typical checks include:
- Visual and dimensional check against the confirmed drawing or sample.
- Contact resistance and coil continuity on relays.
- Trip and reset behaviour on thermal protectors.
- Timing verification on delay devices.
- Packing and label check against the agreed carton specification.
Where a customer requires third-party inspection or a specific test report, we confirm the scope before production so the samples and documentation match the shipment.
Installation, Maintenance and Spare Parts
These components are compact and direct-mounted, so installation is straightforward when the correct part is selected. The protector is fitted with leads and wire nuts for simple installation on the compressor terminal. Relays seat on the terminal cluster and are held by the compressor housing or a retaining clip.
Service practice for this family is replacement rather than repair. Relays and protectors are consumable items with a finite contact and cycle life, and a failed device is normally swapped rather than rebuilt. We therefore keep the range available as repeat-order spares so that service teams and assembly lines can restock without re-qualifying a new part number each time.
Information We Use to Configure Your Solution
To prepare a suitable configuration and quotation, we work from the following project inputs. The more precisely these are stated, the faster we can confirm the matching part.
- Unit type and compressor model, or the original part number being replaced.
- Compressor rating in HP, kW or BTU, and the supply voltage and frequency.
- Required function — start relay, thermal overload protector, delay timer, or a matched set.
- Terminal or mounting dimensions, or a photo and sample of the existing device.
- Trip temperature and current threshold for protector selection.
- Delay period and contact configuration for timer selection.
- Order quantity, packing preference and carton labelling.
- Any inspection, test report or documentation requirement.
Send these details through the enquiry form and we will return a configuration proposal with the matching part numbers and the associated components from the wider PRODUCT range.
Frequently Asked Questions
What is the difference between a relay and a contactor in an air-conditioning circuit?
A relay is an electromagnetic switch used for low-power control and signal switching, usually with fewer contacts and a fast response. A contactor is built for high-power loads, with larger rated current and voltage, more contacts and higher durability for frequent switching. In practice, relays handle control and protection functions while contactors switch the compressor or motor load.
How do I choose the correct thermal overload protector?
Selection depends on the compressor winding being protected. We need the compressor rating, the supply voltage and frequency, and the required trip temperature and current threshold. The mounting style and terminal arrangement also matter, because the protector must seat correctly on the compressor and reset reliably after cooling.
Can you supply the relay, protector and capacitor as a matched set?
Yes. Because we produce metalized polypropylene film capacitors and also supply air-conditioner and refrigerator accessories, we can quote the start relay, thermal protector and run capacitor together as one matched set for a given compressor. This avoids the mismatch problems that occur when components are sourced separately.
Do you support custom configurations or OEM part numbers?
We work from the working point, material and production target rather than from a fixed catalogue alone. If you provide the compressor model, terminal dimensions and required ratings, we will confirm whether a standard item fits or whether a customized configuration is needed, and quote accordingly.
What information should be included with an enquiry?
Include the unit type, compressor model or original part number, compressor rating, supply voltage and frequency, the function required, terminal or mounting dimensions, order quantity and packing preference. A photo or sample of the existing device is the fastest way to confirm a match.
How are these components packed and delivered?
Relays and protectors are packed in cartons sized for the order quantity, with labelling agreed before shipment. Delivery scope, carton marking and any inspection requirements are confirmed at quotation stage so that the shipment matches the approved specification.
