Contactor and relay coils
Bobbin-wound coils for AC and DC operating voltages, with pins or leads to your drawing.
For contactors, relays and motor starters
Custom coils, wound to your drawing.
Wound coils, bobbins and encapsulated windings in enamelled copper wire, and aluminium where weight or cost leads. Manufactured in India, hi-pot tested against your drawing, and delivered to your Incoterm.
- Class B, F or H
- Hi-pot and inter-turn tested
- Measured records
Contactor coil, 230 V AC, class FDWG REV. C
- Wire
- Enamelled copper, class F
- Bobbin
- PA66 GF30, UL 94 V-0
- Critical value
- Resistance 1250 Ω ±7%
- Inspection
- Hi-pot and inter-turn
What we make
Trip and release coils
Shunt trip, undervoltage release and closing coils, wound to your operating voltage.
For MCCBs and ACBs
Solenoid and actuator coils
Coils for plungers, locks, valves and actuators, with the stroke force your design needs.
For interlocks, door locks and actuators
Air-core and bonded coils
Self-supporting coils in bonding wire, with no bobbin.
For sensors, chokes and current measurement
Encapsulated and over-moulded coils
Coils sealed in epoxy or over-moulded in thermoplastic against moisture and vibration.
For outdoor, damp and high-vibration duty
Bobbins and coil formers
Moulded bobbins in flame-retardant plastics, supplied empty or wound.
For your own winding line
Choosing a coil
The wire and the insulation class decide how hot it can run. The tests decide whether it lasts.
Wire for the winding
- Enamelled copper
- The highest conductivity and the smallest winding for the turns.Watch for: Give the enamel build, grade 1, 2 or 3, on the drawing.
- Enamelled aluminium
- Lighter and lower in metal cost, for chokes, reactors and larger coils where weight or metal cost leads.Watch for: About 61% of the conductivity of copper, so the winding gets larger; rare in contactor and relay coils.
- Self-bonding wire
- An enamel with a bond coat, for coils that hold their shape without a bobbin.Watch for: Bonding by heat or current must be controlled to stay solid.
Insulation class for the temperature
- Class B 130 °C
- For coils that run cool or work in short bursts.Watch for: Too low for most continuously energised coils.
- Class F 155 °C
- The usual class for contactor and relay coils.Watch for: The bobbin, tape and varnish must be rated F too, not just the wire.
- Class H 180 °C
- For hot or continuously energised coils.Watch for: Costs more; check that the varnish and bobbin match.
Protection for the environment
- Taped and varnished
- Varnish binds the turns and keeps out dust.Watch for: Ask for vacuum impregnation where the coil sees vibration.
- Encapsulated in epoxy
- A full resin seal against moisture and contamination.Watch for: Voids in the resin cause partial discharge; ask for the hi-pot reading.
- Over-moulded
- Thermoplastic moulded around the winding, with the terminals in place.Watch for: Moulding heat must not damage the enamel.
Specifications
- Types
- Contactor and relay coils, trip and release coils, solenoid and actuator coils, air-core and bonded coils, encapsulated and over-moulded coils, bobbins
- Wire
- Enamelled copper, polyesterimide or polyamide-imide, grades 1–3; enamelled aluminium; self-bonding wire
- Wire diameter
- 0.05–2.5 mm standard
- Insulation class
- B (130 °C), F (155 °C), H (180 °C)
- Bobbins
- PA66, PBT and PET, glass filled; UL 94 V-0 where specified
- Terminations
- Pins, flying leads, lugs or connectors to your drawing
- Tests
- Resistance; hi-pot and inter-turn surge test to your voltage; inductance where specified
- Standards
- IEC 60317 winding wire; IEC 60085 thermal class; dimensions to your drawing
- Quantities
- Prototype builds to mass production
Copper or aluminium wire
Copper makes the smallest coil, and is the choice for contactor, relay and trip coils. Aluminium makes the lightest one, for larger coils.
CopperAluminium
Typical values for annealed copper and aluminium conductor.
Electrical conductivity
100% IACS
about 61% IACS
Density
8.96 g/cm³
2.70 g/cm³
- Copper wire
- The smallest winding for a given resistance and number of turns, and the easiest to terminate. The usual choice for contactor, relay and trip coils.
- Aluminium wire
- About half the weight of copper for the same resistance, but a larger winding. Used in chokes, reactors and larger coils; terminations need welding or crimps rated for aluminium.
Questions buyers ask
What is a hi-pot test?+
A high voltage is applied between the winding and the core or frame, to prove the insulation holds. We test to the voltage on your drawing and report the result with the batch.
What is an inter-turn test?+
A surge test that finds weak insulation between turns of the same winding, which a resistance check misses. Shorted turns are the most common way a coil fails in service.
Which insulation class do I need?+
Class F, 155 °C, suits most contactor and relay coils. Choose class H where the coil runs hot or is energised continuously. The bobbin, tape and varnish must carry the same class.
Can you wind to an existing coil?+
Yes. Send the drawing or a sample. We measure the resistance, wire size and turns, confirm them with you, and make samples for your approval.
Can you supply the bobbin as well?+
Yes. We mould the bobbin and wind it, so the coil arrives as one part with one inspection record.
Can you take a small order?+
Yes. Small, engineering-heavy batches are work we take, from prototype quantities upwards.
Send the drawing
Email us your enquiry at contact@qumek.com. We respond within 12 hrs.
Your enquiries are confidential with us and we proceed with manufacturing only after signing a NDA.
Need a DFM review, a prototype or a test plan before production? See the services.