Torque Motor / Coil Assembly for I/P Converters

Product Specifications

Technical details and manufacturing context for Torque Motor / Coil Assembly

Definition

The torque motor/coil assembly is a critical electromechanical subassembly used in I/P (current-to-pressure) converters. It generates controlled rotational force through electromagnetic interaction between its coil and magnetic circuit, enabling precise pneumatic pressure regulation from electrical input signals. This component is essential in industrial process control, where accurate conversion of electrical signals to pneumatic pressure is required for valve positioning and other actuation tasks.

The assembly typically consists of a coil wound from copper wire, electrical insulation materials, magnetic core materials such as silicon steel, and structural plastics or metals. When electrical current flows through the coil, it creates a magnetic field that interacts with permanent magnets or a magnetic circuit, producing torque on an armature or moving element. This torque is proportional to the input current and is used to position a flapper or similar mechanism that modulates pneumatic pressure.

Key parameters for selection include rated torque (0.5–2.0 N·m), coil resistance (100–500 Ω), supply voltage (24 V DC ±10%), and current range (4–20 mA). Performance characteristics such as linearity (±0.5%), hysteresis (≤0.3%), and repeatability (±0.1%) are critical for precise control. The operating temperature range is -40 to 85°C, with IP ratings from IP54 to IP65 depending on the enclosure. Insulation class F (per IEC 60085) is standard, and the coil material is copper with class 2 insulation. Weight varies from 0.5 to 2.5 kg depending on torque rating.

When selecting this component, verify model-specific values and standards with the legal manufacturer or supplier. Confirm that the rated torque meets the valve stem torque requirement, and ensure the coil resistance and supply voltage are compatible with the control system. Check the IP rating for the intended environment and the insulation class for thermal limits. Always consult the manufacturer's datasheet for exact specifications and compliance with applicable standards.

Working Principle

When electrical current flows through the coil, it creates a magnetic field that interacts with permanent magnets or a magnetic circuit, producing torque on an armature or moving element. This torque is proportional to the input current and is used to position a flapper or similar mechanism that modulates pneumatic pressure. The torque generated is directly proportional to the current, allowing precise control of the pneumatic output.

Common Materials

Copper wire, Electrical insulation materials, Magnetic core materials (e.g., silicon steel), Structural plastics or metals

Technical Parameters

Parameter	Typical range	Notes & selection driver
Rated Torque	0.5–2.0 N·m	Select based on valve stem torque requirement
Coil Resistance	100–500 Ω	Affects current draw and response time
Supply Voltage	24 ±10% V DC	Standard industrial control voltage
Current Range	4–20 mA	Control signal for I/P converter
Linearity	±0.5 %	Deviation from ideal torque-current curve
Hysteresis	≤0.3 %	Lower hysteresis improves repeatability
Repeatability	±0.1 %	Consistency of output for same input
Operating Temperature	-40–85 °C	Extended range available on request
IP Rating	IP54–IP65	Higher rating for outdoor useIEC 60529
Insulation Class	F	Class F allows 155°C max hot spotIEC 60085
Coil Material	Cu	Copper wire, class 2 insulation
Weight	0.5–2.5 kg	Depends on torque rating

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Coil Winding Part
Generates magnetic field when energized with electrical current

Material: Copper wire with insulation
Armature Part
Rotating element that transmits torque to the flapper mechanism

Material: Magnetic steel
Magnetic Circuit Part
Provides path for magnetic flux and interacts with coil field

Material: Soft magnetic materials (e.g., silicon steel)
Terminal Block
Electrical connection interface for coil wiring

Material: Insulating plastic with metal contacts
Permanent Magnets Optional
Supply the fixed field the coil works against on permanent-magnet builds.

Applied To / Applications

This component is essential for the following industrial systems and equipment:

I/P Converter

View system integration details

Manufacturers of Torque Motor / Coil Assembly

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Frequently Asked Questions

What is the function of a torque motor/coil assembly in an I/P converter?

It converts an electrical current signal into a proportional mechanical torque, which is used to position a flapper or nozzle to modulate pneumatic pressure, enabling precise pressure regulation based on the input signal.

What are the typical electrical specifications for this component?

Typical specifications include a supply voltage of 24 V DC ±10%, a current range of 4-20 mA, and a coil resistance of 100-500 Ω. These values should be verified with the manufacturer for the specific model.

How do I select the correct torque rating for my application?

The rated torque should be selected based on the valve stem torque requirement. The available range is 0.5-2.0 N·m. Ensure the torque is sufficient to overcome friction and provide reliable operation.

What environmental conditions can this assembly withstand?

The operating temperature range is -40 to 85°C, and the IP rating is IP54 to IP65 depending on the enclosure. For outdoor use, a higher IP rating is recommended. Always confirm with the manufacturer for specific environmental limits.

Data Basis

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pressure:	0 to 150 psi (compatible with I/P converter standards)
other spec:	Current range: 4-20 mA standard, 0-20 mA optional; Response time: <100 ms; Torque output: 0.5-5.0 Nm (model dependent)
temperature:	-40°C to +85°C

Torque Motor / Coil Assembly

Product Specifications

Applied To / Applications

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