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Tag Archive: electric motor maintenance

  1. How to Save Money on Your Electric Motor

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    Electric motors are the power sources regulating performance, speed, and torque in some of our most important commercial, residential, and industrial machines. But they’re also the single largest consumers of all electricity and, if not maintained properly, can cause costly downtime.

    Fortunately, there are several steps you can take to improve the life and performance of your electric motor, and cut costs significantly. These include:

    1. Soft Starts

    Emotor

    Without the use of a VFD, three-phase motors can start in three ways:

    • Hard start: A direct-on-line start with a very high starting current (6-10 times the rated motor current). This start spurs the motor to get to full speed instantaneously, which can cause belt slippage, heavy wear on bearings and gears, and possible damage to other components in the system;
    • Star delta start: Uses contactors and a timer to switch between star-position for starting (using 30% of starting current and 25% starting torque,) then moving to delta for full load;
    • Soft start: Gradually applies power to the motor and minimizes the initial jolt.

    Soft starts are the safest and most efficient of the three, protecting the facility from blown fuses, excessive voltage, and compromised electrical flow for other warehouse applications. Soft starters use thyristors, semiconductors, and silicon controlled rectifiers to control temperature shifts and electrical current flow as the motor starts, reducing the risk of electrical, technical, and mechanical failure.

    2. Motor Rewinding

    Rewinding a blown or burnt out motor can be a cost-effective and time-saving alternative to investing in a full replacement. Although some are weary of this practice, rewinding a motor, when done correctly, will allow for full restoration of the system’s operational efficiency.

    3. Motor Drive Maintenance

    iStock_000076261135_Small

    Variable Frequency Motor Drives (VFD’s) convert electrical energy into mechanical energy, offering controls to regulate speed and torque. In fact, a properly functioning variable frequency drive can delivery up to 55% in energy cost savings.

    Unfortunately, many businesses put off motor drive maintenance until a system experiences a catastrophic failure. The resulting costs from a complete motor replacement, as well as lost profits from production downtime during installation, are often much more expensive than the price of routine maintenance and repair would have been. If you experience electric motor drive problems, take care of them early to avoid costly repair services.

    Want to Hear More?

    Renown Electric’s team of over 40 experts is committed to serving a diverse range of electric motor applications for a variety of industries around the world. Our latest eBook, 6 Ways to Save Money on Electric Motors, shares additional motor money-saving tips to help you cut costs.

    Simply visit our website to download your copy of this free eBook.



    Download Free eBook
    6 Ways to Save Money
    on Electric Motors

  2. How It Works: CoolBLUE Common Mode Chokes for VFDs

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    Learn how inductive absorbers reduce damage to motor bearings and extend equipment life

    How It Works

    This post continues Renown’s monthly series called “How It Works,” featuring articles that detail the inner workings of motor maintenance services and processes.

    Electric motors are increasingly being equipped with variable frequency drive (VFD) systems for the energy efficiency the combination creates. This efficiency saves money both directly by reducing energy costs, and indirectly by increasing output.

    Yet as most good things do, VFD systems have a small drawback: they create a considerable amount of unwanted high frequency currents to the motors in the form of motor bearing currents. Renown Electric recently partnered with MH&W International to offer a solution to this problem — CoolBLUE Inductive Absorbers.

    Effects of VFD Vibration

    The side-effect that is caused by VFD systems are actually generated by the IGBT’s switching frequency in their common-mode output. Created by the VFD itself, the unwanted current travels to a motor and its bearings via the motor leads that attach the VFD system to the motor.

    Cool Blue Chokes

    When the  common mode current reaches the motor, they travel through both the motor and its bearings in the form of  motor bearing currents. These  currents can be measured using a special instrument called a Rogowski Coil and an oscilloscope.  These damaging currents cause a great deal of electrical noise and, more importantly, a laundry list of mechanical issues that collectively reduce the efficacy and lifespan of the motor:

    — Bearing fluting

    — Bearing frosting

    — Lubrication breakdown

    — Pitting

    — Electrical discharge machining (EDM)

    What are CoolBLUE Inductive Absorbers?

    Inductive absorbers are more commonly known as common mode chokes. They are self-contained electrical inductors used to block and absorb — in other words, to choke — electromagnetic interference (EMI) and radio frequency interference (RFI).

    Both common mode currents, EMI and RFI are the two causes of the EDM effect in bearings created by VFD systems. They do this without blocking differential currents, the currents passing through the power cables that are required to power and control the motor.

    Unlike dv/dt filters, designed to limit voltage spikes in long lead length applications, CoolBLUE cores are designed to specifically choke off the unwanted high frequency currents that are created by the switching of IGBT’s and SCR’s.  This frequency is in the order of 500 kHz to several MHz whereas your control frequency is in the range of much lower kHz.

    CoolBLUE Inductive Absorbers do not block all of the EMI and RFI currents, but they do restrict the majority of them — between 65% and 80%, which is more than enough to prevent them from damaging your motor. When installed properly, CoolBLUE Inductive absorbers will reduce common mode currents.

    How to Use CoolBLUE

    CoolBLUE Inductive Absorbers are extremely simple to install. Disconnect the power cords between the VFD and the motor, insert the phase cords thru the applicable cores — always exclude the grounding wire, leaving it out of the CoolBLUE mode chokes — and reconnect the power cords. The photos below show a few example CoolBLUE installations.

    Cool Blue Installation

    Some installation considerations to keep in mind:

    — CoolBLUE units can be installed on AC, DC, Permanent Magnet motors and Servo Applications

    — Keep the chokes as close to the VFD as possible

    — Install NaLA Noise Line Absorbers for added protection

    — Loop motor leads twice through the CoolBLUE chokes for smaller applications between 1/4hp and 10hp

    CoolBLUE from Renown

    Renown Electric is proud to offer the full line of CoolBLUE Inductive Absorbers to help you to extend the life of your motor today.

    To learn more about CoolBLUE chokes,  download our free Design and Installation Guides today.

  3. Is Your Motor Driving Up Costs and Creating Safety Hazards?

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    Is Your Motor Driving Up Costs and Creating Safety Hazards?

    When your motor isn’t running properly, the business loses time and money — and you also risk the safety of your employees. When it comes to providing efficient, safe operation systems, Renown Electric has the resources required for success.

    Mill Stopping Distances Chart

    As highlighted in Renown’s latest case study, the company was recently approached by a rubber mill owner to help with operation repairs to their outdated control system. Renown’s industry knowledge and ability to implement an effective solution led to the successful restoration of the customer’s system.

    Tackling Safety Risks

    According to the Occupational Safety & Health Administration (OSHA) safety standards, mills are required to cease movement within specified limits. If these limits are not properly enforced, employees risk exposure to hazardous workplace conditions.

    When the rubber silicone mill control and braking system was deemed antiquated, the customer needed quick, convenient assistance to restore operations. Not only did these braking complications slow down production and pose safety risks to the customer’s employees, but it also meant that the mill was not meeting essential OSHA requirements.

    Minimizing Costs

    To quell the safety hazards and production issues caused by the rubber mill’s outdated controls, the customer turned to Mann Electric. After a thorough assessment of the mill’s controls, and with the assistance of Benshaw Controls, Renown concluded that installing a new control panel would comply with OSHA’s strict safety standards.

    By updating the mill’s aging machinery, Renown and the customer extended the motor’s lifetime and provided the customer with increased efficiency and long-term savings. Additionally, the teams were able to use the updated controls in conjunction with the mill’s existing braking resistors, allowing the mill to quickly halt production in emergency situations, as required by safety regulations.

    To read more about Renown’s work with Mann Electric and the rubber mill, the full case study is available for download here.

    Control Panel After

    Why Renown?

    Founded in 1984, Renown Electric has a history of providing consumers with exceptional motor repair and maintenance services worldwide. Our expansive inventory contains both new and used motors and motor parts to support an array of applications. We pride ourselves on our ability to provide high quality services to a variety of customers across a range of industries.

    If you’re experiencing decreased or inadequate performance from your equipment, contact Renown Electric today to learn more about how we can provide you with efficient, affordable service.

  4. Why Would I Keep My Old Motor?

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    Internal Motor

    The current push in today’s world is to upgrade everything to a more energy-efficient state. This is true for cars, appliances, and electric motors.

    If you are deciding whether to keep your old motor or to replace it with a new one, please consider the following:

    Production/Operation Downtime

    Motor replacement requires an associated amount of pre-planning or downtime in operation or production that could be avoided by simply keeping the working motor you already have. Small repairs often take less time than ordering and installing a new motor, which would equal more downtime.

    By pre-planning for the replacement, the best solution — a combination of motor efficiency, cost and performance — can be determined and ordered to avoid rush charges or costly mistakes made when under the pressure of a machine being down.

    Starting Torque

    The starting torque for old motors is generally much higher than starting torque for new motors. This means that replacing your old motor would likely also require installing a new drive into your current machine or equipment, which may not be the most convenient option.

    Often an updated control scheme, as simple as a soft-start, will help reduce the cost of electricity consumed on start-up while maintaining the torque required for the machine.  If a new high efficiency motor is required, careful consideration to starting torque or full load torque may determine that the motor and drive be sized as much as 150% larger in order to achieve the same results as old wound rotor motors.

    Cost

    Although replacing your old motor with a newer motor—particularly one with a more efficient motor—may save your company money in operational costs, it may still not be the most cost-effective solution for you. Often, the cost of maintenance and preventative care for your current motor is much less than the cost of replacing it with a new one.

    Some operating costs can be saved by adding soft starts or VFD’s which have incentives from the power companies that may be as high as 100% of the cost of the VFD.  Often simple things like not stopping and restarting large motors between 11am and 5pm will reduce your energy costs substantially.

    In addition, if the motor is small or only used sporadically, the energy savings of a new motor may not be significant enough to warrant the upgrade. Simple calculations can be made to determine if a motor upgrade would really be the best option.

    At Renown Electric, we offer a selection of the highest quality electric motors to provide you with the motor you need. We are specialists in motor maintenance and replacement.  Please consult one of Renown’s motor specialists to help you determine the best course of action to optimize both cost and performance.

    If you are interested in keeping your old motor and want to make sure that it is well maintained, download our eBook “Preventative vs. Predictive Motor Maintenance.

     

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