Rotor-Mounted Electromagnet Holding Torque With Remanent Pulses
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Solution Overview
Problem
Existing actuators for HVAC applications have high power consumption in the actuation position, which is a disadvantage, especially for safety-relevant applications like fire protection flaps where the switch-on time is 100%.
Innovation Solution
The actuator employs an electromagnet with a coil arrangement and a magnetic coil core, using brief current pulses to establish and extinguish a remanent magnetic field, thereby applying and releasing a holding torque to the rotor, reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanently present holding current is used to hold the electric motor in the actuation position, then the actuator remains reliably positioned, but the power consumption becomes extremely high
Solution Approach 1:
The patent applies periodic pulsed current to the electromagnet instead of continuous current. The control unit sends current pulses at specific intervals (e.g., every 10 seconds) to maintain the remanent magnetic field in the magnetic memory element, thereby maintaining the holding torque. This periodic action reduces power consumption from continuous high levels to intermittent low levels while preserving positioning reliability.
Solution Approach 2:
The patent replaces the conventional electromagnetic holding mechanism (which requires continuous current) with a magnetic memory system. The magnetic memory element stores the magnetic field state, allowing the electromagnet to maintain its holding capability without continuous power supply. This substitution fundamentally changes the energy requirement from continuous to periodic.
2Reliability
If a lifting magnet engages into the reduction gear to prevent automatic movement into the safe idle position, then the actuator holds position reliably, but the power consumption remains high
Solution Approach 1:
The patent replaces the lifting magnet mechanical engagement system with an electromagnetic field-based holding system using a magnetic memory element. The magnetic field interacts with the rotor's magnetic field to create holding torque without mechanical engagement, and the magnetic memory allows this field to be maintained with minimal periodic energy input rather than continuous high power.
Solution Approach 2:
The patent changes the operational parameters of the electromagnet from continuous high-current operation to periodic low-current pulsing. By utilizing the remanent magnetic field properties of the magnetic memory element, the system maintains the necessary magnetic field strength for holding torque while dramatically reducing the average power consumption through parameter optimization.
3Reliability
If an electromagnet with continuous current is used for holding, then the holding torque is maintained, but the switch-on time for safety-relevant applications amounts to 100%
Solution Approach 1:
The control unit implements periodic current pulsing to the electromagnet, maintaining the magnetic field necessary for safety function only when needed rather than continuously. The magnetic memory element retains the field state between pulses, allowing the actuator to maintain safety positioning capability with minimal energy input, thus reducing the effective switch-on time from 100% to brief periodic intervals.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution significantly reduces the electrical power required for fail-safe actuator operation, from approximately 17 kWh per year to less than 1 kWh, while maintaining reliable positioning.
Implementation Method 1
the electromagnet (E1-E3) comprises a coil arrangement (L) with a magnetic coil core (K), by means of the circuit arrangement a first brief current pulse is able to be injected into the coil arrangement (L), so that subsequently a remanent magnetic field remains in the coil core (K)
Implementation Method 2
a remanent magnetic field remains in the coil core (K), in order, in a holding position of the actuator, while a mechanical pre-tensioning is set up, to apply a holding torque with contact (MFH) to the outer side (RA, AA) of the rotor (RO)
Data Source
AI summary
Various embodiments of the teachings herein include an actuator for a flap or for a valve for adjusting a gaseous or fluid volume flow. The actuator may include: a housing; an electric motor disposed in the housing; a downstream reduction gear; and a positioning element with an actuator connection for the flap or the valve. There is an electromagnet adjacent to an outer side of the rotor with a coil arrangement with a magnetic core. There is an electrical circuit arrangement for activating the electromagnet, providing a first brief current pulse, so a remanent magnetic field remains in the coil core. In a holding position of the actuator, while a mechanical pre-tensioning is set up, there is a holding torque with contact to the outer side of the rotor. The circuit arrangement provides a second brief current pulse to extinguish the remanent magnetic field still present in the coil core for releasing the holding torque with contact, forming an air gap between the electromagnet and the outer side of the rotor.