Electric motor FOXY 250 7.2V

Product detailed description

FOXY Brushed DC motors are ideal for a wide range of model applications - for driving aircraft, ships, cars, tanks and other land vehicles with direct drive and gearboxes. When installing and connecting FOXY Brushed motors, make sure not to exceed the permitted supply voltage and current load values.

Motor cooling: During operation, the temperature of the outer casing of the motor should not exceed 80°C. Therefore, it is always necessary to ensure sufficient access of cooling air and its flow around the motor in the model; in the case of ship models, we recommend using water cooling. High motor loads are only possible for a short time. After each flight/ride, it is necessary to let the motor cool down to room temperature before taking off/sailing again.

FOXY 250 7.2 V is a DC electric motor of size "250" with a shaft with a diameter of 2.0 mm and plain bearings suitable for driving indoor models of aircraft with direct drive (propeller 4x3.5") or with a gearbox, for small car and boat models. To control its speed, you will need an electronic controller with a load capacity of 6–8 A. FOXY 250 7.2 V is a suitable replacement for the SPEED 250 7.2 V motor.

The motor set includes: FOXY 250 7.2 V motor, Operating instructions

Voltage (nominal) [V] - 7.2
Voltage (operating) [V] - 3.7 - 7.4
Speed ​​at nominal voltage [rpm] - 15000
Regulator [A] - 6 - 8
Diameter [mm] - 20
Length (case) [mm] - 25
Shaft diameter [mm] - 2
Shaft free length [mm] - 8.5
Weight [g] - 22

DC electric motor with commutator.
In RC models of cars, boats and tanks, permanent magnet motors are used, which also form the stator of the electric motor. The rotor is formed by a coil with wound turns of wire, which thus creates an electromagnet. Electric current is supplied to it through a commutator (rotary switch), which is why this electric motor is also called a "commutator". Its task is to change the polarity of the electric current and thus the polarity of the magnetic field created by the coils. The magnetic resistance created rotates the rotor and thus enables the motor to function. The design of the commutator ensures that the forces acting on the rotor poles always have the same direction. At the moment of polarity switching, the inertia of the rotor keeps the motor running in the right direction. The number of rotor poles affects the smoothness of the motor's operation and the force required for its start-up (engaging torque). The more poles, the smoother the operation. The minimum number is two, the usual number is three to four.

In the data on electric motors, the number of turns is usually indicated, usually with the letter "T". This is important in determining the appropriate motor for a specific type of model, usually a remote control car model. The number of turns determines (with the same motor size and the same power supply) the speed of its rotation. The more turns, the slower the motor rotates, but at the same time it has a higher torque. So a fast drift car will use a motor with fewer turns than a slow expedition car, where a high torque is needed. If necessary, gearboxes are also installed in the models, which allow combining the advantage of high power and the need for higher speed (e.g. RC truck models).

When using these electric motors, it is advisable to follow some rules so that the motor lasts as long as possible and does not wear out prematurely.
A new electric motor, or a model with such a motor, should first be run in. Current enters the motor on the commutator pads using so-called carbon brushes, which may not have a perfectly adjusted shape from the factory. If a new motor is loaded to the maximum without prior running-in, the commutator surface or carbon brushes may be damaged due to excessive "sparking". It is advisable to use a new motor for the first runs under moderate load at low speeds to allow the carbon brushes to settle on the commutator as perfectly as possible. This way, the carbon brushes will wear out less and last longer.

Since the stator is made of permanent magnets, it is good to know that these magnets gradually lose their "strength". However, temperature also has a great influence. Every electric motor heats up during operation and can reach a temperature of up to 60 degrees Celsius (therefore, under no circumstances should the motor be touched with bare hands after driving!). However, if the motor is not cooled, or cooled insufficiently, or if it is driven for a long time at maximum speeds, it may overheat and thus weaken the magnets. The motor will then no longer achieve its previous performance even after cooling down. Of course, there is a risk of damage to other parts of the motor due to high heat. It is therefore advisable to change the load mode, or rather drive with two smaller batteries with a break for replacement and cooling, rather than with one large-capacity battery for a long time at full power.

The speed of the electric motor is directly dependent on the supply voltage, so it is good to use these motors in the voltage range specified by the manufacturer. In car models, the standard is to use 7.2 - 8.4 V, in the case of other voltages, the motor in the model is adapted to it and this must be remembered when replacing it, if necessary.

Running-in of a new electric motor
Before starting to use a DC electric motor, it is clearly recommended to run it in. Some manufacturers require it as a condition for recognizing a possible motor complaint.

The purpose of running in the electric motor is to ensure that the rotating parts settle well, the friction surfaces of the contacts are smoothed, and the carbon brushes are ground to the correct shape.

Procedure:
-If you have a new RC car or boat model in which the motor is already installed, proceed as follows. Place the model on a support so that the wheels are rotating above the surface. Let the engine run at the lowest possible speed for at least 20 - 30 minutes. Then you can drive the model for 20 - 30 minutes at a lower speed first and gradually increase the speed. Drive the model at full power only after the running-in phase has passed.

-If you have a new engine that has not yet been mounted on the model, you can run it in the traditional proven way submerged in water. Connect the engine to the ESC controller and lower it vertically by the cables into a container of clean water. Spin the engine at low speed and let it run for 10 - 15 minutes. Then you can gradually increase the speed for a few minutes to the maximum. Finally, remove the engine from the water and let it run for a while to blow the water out of the engine. You can mount the run-in engine in the model and you can drive at full power right away. You do not have to worry about the engine being submerged in water. It will function normally and the water will cool it during the run-in. In addition, it will flush out carbon particles during grinding (the water will become visibly darker).