Customized Motion Control for 34 Years
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Frequently Asked Questions
1. Why should I choose Astromec to build my motors instead of another company ?Astromec has been ISO certified since 1994 and is a leader of high quality motors that meet some of the most demanding applications of today. We provide excellent customer service, high level engineering support, and ON-TIME DELIVERY at a very competitive rate. Back to Top
2. What types of motors does Astromec manufacture ?We design and manufacture fractional horsepower (under ½ HP) direct current (DC) and alternating current (AC) motors. Some of these motors incorporate a wire-wound stator to create the electromagnetic field necessary for the generation of torque while others utilize permanent magnets. We design and manufacture both brush-type and brushless-type DC motors. Back to Top
3. Does Astromec offer other motion control accessories?Yes, Astromec provides gearboxes, brakes, clutches, tachometers, encoders, and actuators for most of our motor products. Back to Top
4. Does Astromec design motors for specific applications?Absolutely. Custom design is the specialty of Astromec. In fact, we do not build catalog or "off-the-shelf" motors. Each product we design and manufacture is tailored to meet the individual needs of each customer's specific application. In order to maximize our responsiveness and provide the most cost-effective solution for your application, we often derive your unique product from a large variety of brush and brushless DC motor designs we have created for previous applications. This provides cost effective and timely designs Back to Top
5. What is a typical lead time for prototypes and production motors?The complexity of design requirements for each unique application makes the lead time for prototypes and production units highly variable. However, we typically provide prototypes in as early as two weeks and production units in as short as six to eight weeks. We are arguably the fastest, most responsive custom motor design company in the business. Back to Top
6. How do I figure out what size motor I need?The answer to this question involves many variables that need to be factored into the final equation. These variables include: the minimum space available for the motor, the voltage supply, operating speed and the torque requirement, and the operating duty cycle (time on/off). The operating speed and torque requirement is used to determine the power needed and this is balanced with the space available in your application. All these application specific factors, in addition to the production manufacturing quantities, dictate the cost of a final motor solution. In general, the more power required in a given space and the smaller the production quantities are the higher the cost of the motor solution. Since Astromec is a custom motor design company call one of our engineers; we can help you figure out what your motor requirements might be. If an "off-the-shelf" solution exists for your application we will be happy to point you in the correct direction. Back to Top
7. What type of product information can Astromec provide to me?Each motor we make is tailored to meet the individual needs of each customer's specific application. In order to maximize our responsiveness and provide the most cost-effective solution for your application we often derive your unique product from a large variety of brush and brushless DC motor designs we have created for previous applications. This provides cost effective and timely designs. We do not sell "off-the-shelf" or catalog motors; each of our products is designed to meet your specific needs. Back to Top
8. Can Astromec transmit and receive files via the Internet?Yes. Astromec has a fully integrated internal e-mail system that is connected to the Internet. We also have the capability to post files to private accounts so that our customers can retrieve information at their leisure. Back to Top
9. How long has Astromec been in business?Astromec was founded in 1967, initially designing and manufacturing motors and accessories for aerospace applications. Today we manufacture products for aerospace, commercial aviation, medical, and numerous industrial/commercial marketplaces. Back to Top
10. Where are Astromec's manufacturing facilities?All design and manufacturing is done at our facility in Carson City, Nevada, USA. Back to Top
11. How does a brush motor operate?A typical brush-type motor utilizes a wire-wound armature that is terminated on a commutator. The stationary electromagnetic field of the motor can also be wire-wound like the armature (called a wound-field motor) or can be made up of permanent magnets (called a permanent magnet motor). In either style ( wound-field or permanent magnet) the commutator. acts as half of a mechanical switch and rotates with the armature as it turns. The commutator is composed of conductive segments (called bars), usually made of copper, which represent the termination of individual coils of wire distributed around the armature. The second half of the mechanical switch is completed by the brushes. These brushes typically remain stationary with the motor's housing but ride (or brush) on the rotating commutator. As electrical energy is passed through the brushes and consequently through the armature a torsional force is generated as a reaction between the motor's field and the armature causing the motor's armature to turn. As the armature turns, the brushes switch to adjacent bars on the commutator. This switching action transfers the electrical energy to an adjacent winding on the armature which in turn perpetuates the torsional motion of the armature. Back to Top
12. How does a brushless motor operate?A brushless motor operates much in the same way as a brush motor. However, as the name implies there are no brushes (and no commutator). The mechanical switching function, implemented by the brush and commutator combination in a brush-type motor, is replaced by electronic switching in a brushless motor. In a typical brushless motor the electromagnetic field, created by permanent magnets, is the rotating member of the motor and is called a rotor. The stationary winding then becomes the portion of the motor wherein the electrical energy is commutated. This commutation is accomplished via electronic switches since there are no moving interfaces between the winding and these switches. In a brushless motor, the trick becomes to know when to switch the electrical energy in the windings to perpetuate the rotating motion. This process is mechanically, and simply, resolved in a brush-type motor by the motion of commutator past the brush as the armature turns. This is typically accomplished in a brushless-type motor by some feedback means designed to provide an indication of the position of the magnet poles on the rotor relative to the windings. A hall effect device (HED) is a commonly used means for providing this positional feedback. Astromec's brushless motors usually incorporate HEDs. However, in more sophisticated applications, our brushless motors have been commutated without sensors or with the use of an encoder for positional feedback. Back to Top
13. Why should I choose a brushless motor over a brush motor?The are many factors that affect the decision to select a brushless motor for a particular application. A brushless motor is often used when high reliability, long life and high speeds are required. The bearings in a brushless motor usually become the only parts to wear out. These bearings can last thousands of hours depending on shaft load and environmental conditions. Often in a brush-type motor, the brushes and the commutator become the components determining the motor's life. In applications where high speeds are required (usually above 30,000 RPM) a brushless motor is considered a better choice. As motor speed increases so does the wear of the brushes. Additionally, at higher and higher speeds it becomes increasingly more difficult to keep the brushes from bouncing on the commutator bars as they transition from segment to segment. Thus, this brush bounce phenomena often becomes the practical limit of speed in a brush-type motor. The mechanical switching of brushes on commutator segments often generate objectionable electrical and audible noise. In these instances a brushless motor can usually sound quieter and provide less of a disturbance to other electrical equipment in the vicinity. In applications where weight and/or size of the motor itself is limited, a brushless motor's commutation control can easily be separated and integrated into other required electronics, thereby improving the effective power-to-weight and/or power-to-volume ratio achievable by a conventional brush-type motor. All these benefits have a cost. A brushless motor package (motor and commutation controller) will usually cost more than a brush-type, yet the cost can often be made up in other advantages. For example, in applications where sophisticated control of the motor's operation is required, the electronics necessary for a brush-type motor can typically end up costing about the same as the electronics required to control a brushless motor. In these instances, a brushless motor clearly has the upper hand. Back to Top
14. What are the advantages/disadvantages of a permanent magnet (PM) motor?There are several typical advantages of a PM motor. When compared to AC or wound field DC motors, PM motors are usually physically smaller in overall size and lighter for a given power rating. Furthermore, since the motor's field, created by the permanent magnet, is constant, the relationship between torque and speed is very linear. This linearity makes it much easier to predict a motor's performance and therefore easier to control. In applications where backlash due to gear slop cannot be tolerated, a PM motor can provide relatively high torque at low speeds. Since PM motors do not have the copper losses associated with wound fields, their electrical efficiency is often as much as 10% higher. Finally, the PM field provides some inherent self-braking when power to the motor is shutoff. There are several disadvantages to consider. First, high current applied to a PM motor during a stall condition or during instantaneous reversal can damage some types of magnet materials. Furthermore, some magnet materials can be damaged when subjected to excessive heat and some loose field strength if the motor is disassembled. Back to Top
15. What is meant by the term " gearmotor"?The term gearmotor is used to define a motor that has a gear reduction system (or gearbox) integrally built into the motor. The gearbox increases the torque generating ability of the motor while simultaneously reducing it's output speed. Astromec routinely designs gearboxes into our motor products to provide the best solution for each particular application. Back to Top
16. What is meant by the term - "servo motor"?The term servo motor is used to define a motor that is specifically designed to operate in a closed-loop control environment where a feedback device, usually monitoring speed, current, position, etc. is used to control the performance of the motor. Servo motors are usually designed to be particularly sensitive to the systems control signal voltages, especially at or near zero speed. Back to Top
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