MicroMo Electronics' DC motors differ from conventional, iron rotor DC motors in that they are equipped with an ironless, self-supporting, skew-wound copper coil. Because of this construction, the rotor is very light yielding a low moment of inertia. The rotor also rotates smoothly without cogging.
MicroMo Electronics offers the following DC Motors:
High acceleration and deceleration due to the low moment of inertia
Low electromagnetic interference
Low inductance
High efficiency
Linearity between voltage and speed
Linearity between load and speed
Linearity between load and current
Small torque ripple due to the multi-segment commutator
Compact design
Precious Metal and Copper/Copper Graphite Commutation Systems
For low power motors, commutation systems using precious metals are chosen because of their low contact resistance. For higher power applications a DC motor with a copper commutator and copper-graphite brushes will achieve longer life. The copper graphite brush commutation system is also more forgiving under overload conditions.
Performance Lifetime
The performance lifetime of coreless DC motors depends on:
Operating point - torque, load, and speed
Operating conditions - duty cycle
Ambient conditions - environment, shock, and vibration
Method of integration into other systems - ie. how is the DC motor mounted into the system
Since any combination of the above mentioned parameters may occur, it is impossible to give guaranteed lifetime figures.
The lifetime depending on the application type may exceed 10,000 hours. Higher speeds cause accelerated mechanical wear, resulting in reduced lifetime. Excessive high current and temperature shortens the lifetime. On the average, lifetime of up to 1,000 hours for precious metal brushes, and more than 3,000 hours for graphite metal brushes can be expected when the motors are operated within recommended values indicated on the data sheets.
It is advisable that the current under load in continuous operation should not be higher than one-third of the stall current. In motors with graphite brushes the relationship between stall current and current under load depends on the delivered power and frame size. The motors should not be operated at the stall torque MH, otherwise after a short period of time, the commutation of the windings could be damaged. The motor develops its maximum power P2MAX, at exactly half the stall toruqe MH which also corresponds to half the speed. For reasons of life performance, this working point should only be selected for intermittent periods. For exceptional long life performance, brushless DC motors are available.
Operating Information
Temperature - Humidity
The proven design of the bonded multi-layered skew wound rotor retains a high degree of mechanical rigidity even at elevated temperature. The majority of the rotors have an epoxy-coated coil for a temperature range up to +125°C. Galvanic zinc plated and passivated housings give protection against corrosion housings give protection against corrosion in environments with a relative humidity up to 80%. Nickel plated housing in environments with a relative humidity of up to 98%. For applications under extreme environmental conditions, special executions can be offered upon request.
Commutator - Brushes
Multi-segmented precious metal or copper commutators and multi-fingered precious metal or copper impregnated graphite brushes are used. The life performance depends mainly on the speed (mechanical wear) and current (electro-erosion) applied to the motor. For extended lifetime, reinforced brushes, commutators, and special commutator lubrication are available. The commutation signals of precious metal brushes and graphite brushes do not directly compare. Precious metal commutation generally has a cleaner signal than graphite commutation. Current consumption, commutation signals, and noise level of individual samples are not necessarily representative of production quantities.
Bearings - Lubrication
The sintered metal bearings (lubricated under vacuum) and the ball bearings are permanently lubricated with special oil. Relubrication is not necessary and not recommended. The use of non-approved lubricants on the motors can negatively influence their function and lifetime. Ball bearings are recommended for continous operation at low and high speeds and for elevated radial shaft load.
Position of operation - Mechanical load - Vibration
The motors can be operated in any position. Ball bearings are recommended for high radial load requirements. Vibrations of 5-10 g at frequencies up to 1,000 Hz will not limit the function of the motors. However, as these motors are precision engineered products, they should be handled with care to ensure the desired performance.
Solder terminals - Lead wires
The motors are supplied standard with solder terminals and optionally with lead wires. The plastic cover with the solder terminal withstands instantaneous temperatures of soldering or welding, provided the equipment used has the adequate power.
Mounting of the motors
If the motors are mounted on the front-face holes, the screws must not exceed the indicated depth, otherwise the magnet will be displaced resulting in damage to the motor.
Flat, Coreless DC Motors
Flat, coreless DC motors uses an ironless rotor technology with three flat, oval coils provides the basis for leading-edge performance in applications with minimal space.
The flat, coreless rotor rotates in an axially directed magnetic field with a minimum moment of inertia – without cogging or iron losses. The precious metal commutation is designed to allow deployment at ultra-low starting voltages, which is made possible by the reduced brush contact resistance. Therefore, Flat, coreless DC motors are particularly suitable for battery operated portable devices.
High Power Permanent Magnet DC Motors
Permanent Magnet DC Motors offer good efficiencies and a high peak load through the use of premium ferrite materials and optimized magnet systems. The steel tube housing with externally accessible brushes provides for a rugged, high-quality design. The Permanent Magnet field wound DC motors are rated in power from 10 W to 750 W with mounting options for worm, planetary, and spur gears with torques up to 130 Nm as well as brakes, incremental encoders, and tachometers.
NEW! DC Motor Application Considerations
A 4-page tutorial providing general guidelines for the selection of DC motors including: - Audible noise - Electromagnetic interference - Motor service life
[DC Motor Application Considerations]
NEW! How To Select A DC Motor
A 4-page tutorial describing the basic calculations and inputs needed to properly size a DC motor including: - Available voltage - Output torque required - Output speed required - Physical envelope available - Operating temperature
[How To Select A DC Motor]
NEW! Motor Calculations
A 9-page tutorial detailing the steps needed to properly size and select a DC motor including: - Calculating the mechanical power requirements - Torque-speed curves - Numerical calculation - Sample calculation - Thermal calculations
[Motor Calculations]
NEW! Development of Electromotive Force
a 5-page tutorial detailing the basics of the development of electromotive force including:
The new Series 2607/2619...SR flat DC Micromotor with precious metal commutation from FTB features a height of only 7 mm with an outer diameter of 26 mm. [Series 2607/2619...SR Flat DC Micromotor]
Powerful Yet Small - 10mm DC Micromotor with Precious Metal Commutation
With an external motor-diameter of only 10 mm and a length of 24mm, the power to volume ratio is truly impressive. [more]
Powerful SR DC Micromotor with Integrated Encoder
The new series 2232...SR motor with available integrated encoder IE2, adds its name to the powerful line up of SR DC Motors from FAULHABER.
[Series 2232...SR]
