These motors are used in diverse applications including robots, industrial motion control, factory automation, semiconductor manufacturing, motorized scooters, go karts, and electric bicycles.

  We offer four different motors:

Horsepower, Torque, and RPM

The horsepower and torque of our three high-performance motors are higher than other reversible, permanent magnet motors in this size range. Some gearmotors can't even achieve 3840 oz-in, and that is after multiplying the torque with a gearbox. (Please note that this is the theoretical peak torque when stalled. Operating any high-performance motor while stalled will damage it).

Usually, the higher the voltage and RPM of a motor, the higher its efficiency will be. Some motors have high efficiency, but at a no-load speed of 20,000 RPM or more. Gearing such high RPM down to a usable speed takes several stages of gear reduction. This is heavy and wastes power and the efficiency advantage usually disappears. The tricky part is making a moderate speed motor that is also highly efficient. The relatively low RPM of our motors makes any required speed reduction much easier. Using one or two stages of roller chain and sprockets is an easy and inexpensive way achieve speed reduction.

The C40 being tested on a dynamometer

Solid Construction - Easy Mounting

These motors are made from two sturdy aluminum castings and a seamless body. The long output shaft makes it easy to mount pulleys, sprockets, and gears in just the position you need them. A second 1/2" diameter shaft extends 3/4" from the rear of the C40 and S28 motors. This is very handy for mounting encoders, fans, tachometers, brakes, or other devices. If you don't need the rear shaft, you can cut it off flush with the face of the motor.

Some motors use an internal fan to keep them from overheating. These motors are efficient enough to operate without a fan. This has three advantages: (1) The motor housing is completely sealed so nothing can enter the motor and damage it; (2) The sealed motor tends to contain radio-frequency noise that would otherwise escape through the ventilation holes; (3) Increased efficiency because the energy that would normally be used to run the fan generates mechanical power instead.

C40-300                                             

The armature rides in two large high-quality ball bearings and it is dynamically balanced using epoxy rather than by the normal method of drilling the laminations. Drilling can cause eddy currents in the laminations, which increase motor heating.

Each of the four brushes in the C40 and S28 motors has its own heavy-duty motor lead made from mil-spec 10-gauge flexible stranded wire, (12-gauge for the S28s). Each copper strand is coated with pure silver to protect against oxidation and to get the lowest possible resistance in crimped connections. These leads are flexible but not "floppy", so they tend to stay where you put them. The four leads have high-temperature Teflon insulation rated for 200° C, (392° F), so they can handle high current without melting.

Detailed drawings are available here: C40 drawing, S28-400 drawing.

Efficiency

Getting high efficiency from a low-Voltage motor is not easy. There are many factors that effect efficiency. We have optimized each of these factors to achieve the amazing efficiency of these motors.

As you can see from the above chart, the efficiency of the motors is very high over a broad range of power. Our motors are shipped with neutral timing so the performance is the same in both directions.

The C40 and S28 armatures are wound with very heavy gauge wire, and all the space in the armature is used. We left no power-robbing "empty air" in the slots; they are packed with copper! The S28s have skewed armature laminations to eliminate the heavy "cogging" that results from using the extremely powerful neodymium magnets. The C40 motor uses straight laminations, but the cogging is kept to a very low level by using a 42-bar commutator. The huge 1.75" diameter of the commutator combined with the four massive brushes and the 42 bars enabled us to get high power and high efficiency from this smooth-running motor, (the S28s have 21 bars). As far as we know, the C40 and S28 motors have the highest efficiency of any 24-volt reversible permanent magnet DC brush motors in their size ranges.

Another benefit of the four-brush, 42 and 21-bar designs is the absence of excessive electrical noise. While all motors produce some electrical noise, cheaper motors with fewer commutator bars are more likely to send noisy voltage spikes back to your controller.

Radio-frequency noise in the C40 and S28 motors is further reduced by the use of internal capacitors. These motors come with four capacitors built right in to the motors. Each of the four brushes has a capacitor wired to its nearest neighbor on each side. This makes the motors ideal for radio-controlled applications.

Using rare earth magnets is normally the only way to get high efficiency from a low-Voltage motor. While these magnets are very strong, they are also extremely expensive. We use neodymium rare earth magnets in the S28 motors but the cost of rare earth magnets in a motor the size of the C40 would have been astronomical. We studied the alternatives and decided to go with a high-energy-product ferrite magnet known as "T9". The T9 magnet material along with the other design features listed above have enabled us to achieve the same high efficiency of rare-earth in a much less expensive motor.

Motor Control

     S28-150
The high current these motors are capable of drawing requires the use of high quality controllers.

                                                                                         S28-400
But even if your application is limited to just 20 Amps or so of available current, these motors will still produce more power than any other small PMDC brush motor available, (because of the high efficiency).

Choosing a motor

The S28s have incredible power to weight ratios and for weight-sensitive applications these would be the best choice. The C40 weighs more than the S28s, but in some cases this is advantageous. The higher motor mass will decrease the rate of motor heating for a given level of power. If you need high power for several minutes or moderate power for an extended time, the larger C40 is a better choice.

Detailed drawings are available here: C40 drawing, S28-400 drawing.

Technical Specifications:

E-150 Sprocket and Key	E-150 Economy Motor
The 12mm bore of this 9-tooth sprocket fits the shaft of the E-150. The sprocket works with #35 roller chain and it comes with the required 3mm key.

Warrantee
The motors are warranted to be free from manufacturing defects, and fully operational when you receive them. AmpFlow gives no other warranty, either expressed or implied. Warranties are not transferable. In no event shall AmpFlow's liability exceed the buyer's purchase price, nor shall AmpFlow be liable for any indirect or consequential damages.

Ordering
Shipments must be to a street address; we can not ship to a PO Box. We offer Free Shipping (standard domestic), on single orders of 8 or more motors. Please allow 7-10 days for orders shipped by UPS ground, 3-4 days for orders shipped by 2nd day air, and up to 14 days for international orders.