Although high quality variable speed motors cost a lot more than their low quality counterparts, it should not be seen as an unnecessary expense, but rather as an investment into the future of your business of which the benefits will be reaped over the long term.  The benefits you will get for spending more money include using the variable speed motors for a very long time before having to replace it eventually.  As such, it should be quite obvious that high quality variable speed motors will not malfunction or show signs of breakage as easily as is the case with low quality versions.  High quality variable speed motors will also indirectly help you to satisfy your clientele or customer base, seeing as work of a higher standard will be done in a shorter period of time than was the case before.

Consider purchasing Variable Speed Motors from EP Normand

Being a trusted supplier of various industrial and electrical appliances for a number of years already, you should most definitely consider purchasing variable speed motors directly from EP Normand.  Due to the fact that we have gained the reputation of being extremely reputable, you can have the peace of mind knowing that the variable speed motors supplied by us are all of a truly high standard of quality.  There is an old saying which states that in order to become the best you need to surround yourself with the best.  Nowhere in the business world is this more applicable than when conducting business with EP Normand.  Thus for all your needs relating to variable speed motors, do not hesitate to contact EP Normand.

Variable Speed Motors available from EP Normand:

• MAC-QE Variable Speed AC Motors
• MAC-QI Variable Speed AC Motors
• MAC-QS Variable Speed AC Motors
• MCC Variable Speed DC Motors

Upon trying to select the right industrial motor, you need to realize that the decision you make will ultimately have far reaching consequences.  Choosing right the first time is thus of paramount importance as far as industrial motors are concerned.  There are a few things which determine your ultimate decision concerning the selection of the right industrial motor.  These include, among others, compatibility of the industrial motor with existing equipment, previous experience, and of course personal preference.

Contact EP Normand to help you select the right Industrial Motor

If you have trouble selecting the right industrial motor, you can always ask for some helpful advice from the friendly staff working at EP Normand.  Being a reputable supplier of various industrial products, including industrial motors, EP Normand is able to make your decision easier with regards to selecting the right industrial motor.  Having unique needs, you cannot make such a decision based on what your industry competitors are doing, seeing as they probably have unique needs of their own.

Something which is very important when selecting the right industrial motor is to always invest in high quality products, no matter whether you eventually decide on AC motors, DC motors or brushless motors.  Although low quality industrial motors will cost less, it should come as no surprise to you that it will not stand the test of time.  Thus it will break down and corrode quite easily, especially if it is to be used in harsh conditions and environments.  Some individuals view the purchase of high quality industrial motors as an unnecessary expense when having to select the right industrial motor.  However, it should rather be seen as an investment into your businesses future of which the benefits will be reaped in due time.  By purchasing high quality industrial motors, you can at least have the peace of mind knowing that one aspect of your selection of the right industrial motor is taken care of.

Some of EP Normand’s products:

• Servo Motors
  • SMH / SMB Servo Motor
  • MH / MB Servo Motor
  • NX Servo Motors
  • Torque Servo Motors
• Variable Speed Motors
  • MAC-QE Variable Speed AC Motors
  • MAC-QI Variable Speed AC Motors
  • MAC-QS Variable Speed AC Motors
  • MCC Variable Speed DC Motors

AC drives are used particularly in small-scale output (the opposite of bulk production) where one machine may be used to perform several different tasks. AC drives combine high performance and efficiency with ruggedness, simplicity of operation, and low cost. Their main purpose is to control the speed, torque, and direction of rotary machinery such as lathes, mills, pumps, conveyor belts and printing presses.

There are benefits and drawbacks to both AC and DC drives. For example, AC drives are held in high regard for their dependability, compact size, and low maintenance, while DC drives are praised for their low cost, simplicity, and versatility.

AC Drives

3-phase AC induction motors require virtually no maintenance. They are also smaller and lighter than DC motors. This means that they are great to use in areas that are either hard to reach, or have space or weight restrictions. Because they are brushless, they are also the preferred drive system for high speed applications, seeing as they have no commutator problems. Special AC drive casings are available at a low cost to be used in areas at risk of corrosion, explosion, or moisture. This makes them ideal for water systems and chemical plants.

AC drives are the popular choice of drives in areas where loads are variable, or where there are long runs of light loads. These actions cause wears on the brushes and commutators of DC motors. AC drives are also the better choice in systems that require several motors to run at a simultaneous speed.

DC Drives

Not only are DC motors less complex than AC motors, but they are generally cheaper as well. This makes them extremely useful for small companies. DC drives are also the better choice regarding regenerative loading applications, which include escalators and conveyor belts, or in areas where very sensitive control is needed.

If the number of conductors in the secondary is increased, the output potential is increased in direct proportion.  The inverse is also true.  This is called transformer action. It is because of transformer action that a current is created in the rotor (secondary circuit) of an AC induction motor and a resulting magnetic force, within and around the rotor, is also created. 

If the magnetic field reaches maximum strength and quits growing, the current flow in the secondary returns to zero regardless of the level of current flow in the primary.  This basically means that there is a secondary current induced only when the magnetic field around the primary is either increasing or decreasing in size.

Modern drives have applications built into them, thus facilitating installation in a fast and straightforward manner.  Setting the drives up using the free software provided by Parker SSD Drives is just as easy. 

Like their predecessors, the modern drives were set up initially for V/f operation.  With these modern drives, motors are able to run close to their original maximum design speed, which had not been possible with the previous drives.  Installation of modern drives will save you a lot of money because of their greater energy efficiency.  Compared with older SSD Drives, the modern drives were much more efficient in terms of energy consumption.  Continuously improving ways in which to save energy is of the utmost importance for most companies.  Another indicator of their efficiency is that the modern drives are much quieter in operation than any of their predecessors.  Although low noise levels are not always one of the requirements in every application of most companies, the modern drives are undoubtedly the sign of an efficient, well-built drive.

A lot of users of older variable-speed drives believe that there is little reason to update their existing installations.  However, as the experience of most companies with Parker SSD drives has shown, modern drives can not only improve reliability, but they can also deliver valuable energy savings and even sometimes enhance the capacity of existing plants.

Important operating specifications worth considering when searching for DC drives include open loop control, position feedback, tach or velocity module, BEMF or voltage control, torque or current control mode, switching frequency, bandwidth, maximum speed, continuous power, continuous output voltage, maximum continuous output current, and peak output current.  Open loop control makes use of a tachometer or other device to monitor motor speed, rather than using position feedback to control the motor.  Position feedback uses position, force, or other feedback to control motor, in addition to speed sensors.  Use of feedback is referred to as closed-loop control.  A tach or velocity mode gives direct feedback of motor speed.  A drive with BEMF or voltage control can run without a tach using the motor’s Back EMF voltage.  A torque or current control module has constant current control and uses current feedback.  Switching frequency is specified for drives with digital output waves, i.e., PWM.  The bandwidth is the frequency range over which the device meets its accuracy specifications. Accuracy is degraded at lower and lower frequencies unless the device is capable of DC response, and at higher frequencies near resonance and beyond, where its output response rolls off. Frequencies in the database are usually the 3dB roll-off frequencies.  The maximum device speed is the speed when the drive is burdened with no external forces, such as weight.  The continuous power is the maximum amount of power the device can output continuously.   The continuous output voltage is the maximum voltage the device can output continuously.  The maximum continuous output current is the maximum current the device can output continuously.  Maximum current value may require additional cooling.  The peak output current is the peak current the device can output.

Before fitting variable frequency drives to existing motors, you should make sure that you match the electrical characteristics of the motor and frequency converter.  If not, the risk of premature failure becomes very real to the system.  One such problem is that the high rate of switching of the inverter PWM waveform can lead to problems, especially with regard to older motors, whose insulation systems may deteriorate more rapidly due to the rapid rate of voltage change; the adoption of filters in the output of the inverter can eliminate this problem.  In addition, voltages can be induced in the shafts of larger motors, potentially leading to circulating currents that can damage bearings.  This can be addressed by using insulated non-drive-end bearings and, for higher powers (over 100kW) common mode filters may also be required.

Other electrical problems that may occur due to retrofitting variable frequency drives are that the rate of the PWM wavefront rise can cause electromagnetic disturbances, which requires adequate electrical screening (screened output cables).  Long cable runs can result in ‘transmission line’ effects that cause damaging raised voltages at the motor terminals.

After addressing potential problems, it is worth mentioning that when installed in the correct manner by a team that is familiar with the above issues, variable frequency drives can also solve problems in addition to saving energy.  For example, the average power factor in a building is only 90 per cent; an inverter has a unity power factor of 99 per cent, thereby ensuring the maximum performance for a pump is attained.