ACROSS THE LINE MOTOR STARTERS

The simplest type of motor starter is an across the line starter or a direct on line (DOL) starter. It is also the starter that experiences the highest current during the motor starting process.

These starters apply the full line voltage to the motor terminals. A DOL motor starter often contains protection devices and in some cases, it has condition monitoring. OL starters

Why Do Motors Fail?

Electric motors are complex machines with multiple moving parts. They are vulnerable to  common performance issues that reduce their life span. Everyone wants their motors to last a long time and knowing the problems that can affect their dependability and operation is important. There are six main issues that can result in premature motor failure.

Regular maintenance is important to keep a variable frequency drive (VFD) operating efficiently and effectively.

Selecting the right type of VFD for the job is the first step. For outdoor applications such as oil and gas operations, irrigation, wastewater treatment and mineral extraction, the correct NEMA-rated enclosures should be specified to protect the VFD from dust, dirt and debris. 

Motor Operation in Hot and Cold Climates
According to Worldwide Electric motors, the temperature range of a motor is clearly defined by the instruction manual and the motor nameplate. An ambient operating temperature range of -20° C to 40° C is most common for general purpose industrial motors. 

This temperature range is consistent with most common industrial applications. Applications where ambient temperatures exceed 40° C need special consideration for components like the seals, fan, insulation and the grease in the bearings.

Even though a motor’s ambient operating temperature is in most cases limited to 40° C, general purpose industrial motors have components, like motor windings, that by design get much hotter.

The difference between the ambient temperature and the average temperature of the windings under full operating load is known as temperature rise. Inevitably, some of the energy provided to a motor is lost as heat, and a powerful or inefficient motor can have more than 105° C in permissible temperature rise for Class F insulation systems.

To compensate for the temperature rise, manufacturers select durable, insulative magnet wire, ground insulation, varnish, lead wire insulation, tapes, strings and sleeves for motor assembly.

Each of these components is assigned to a National Electrical Manufacturers Association (NEMA) MG1-2016 insulation class, which evaluates motor components based on 20,000 hours of rated motor service life operating at the maximum permissible operating temperature.

The standard also acknowledges that the temperature rise may be locally higher on some components, so there is a hotspot allowance when selecting insulation temperature class for motor components.

For example, a motor with a 100° C temperature rise would require class F materials, as the standard assumes a 40° C ambient temperature, and the class provides 15° C tolerance. Every 10° C above the rated operating temperature will shorten the motor life by half.

Running a motor in cold and freezing conditions raises additional concerns, and overheating remains a major risk. Overheating can occur if ventilated motor enclosures are covered in ice or snow. Overheating can also be caused by an overload situation or pushing the motor into service factor. It is important for operators to continue to follow motor operating specifications as normal in cold weather.

When temperatures are lower than -20° C or higher than 40° C, operators need to take extra care of components such as grease, bearings, seals, fans, insulation or leads. 

EXPLOSION PROOF MOTORS

If you are looking for a general-purpose motor for a reasonable cost, Open Drip Proof (ODP) motors may be a good option. Available in a wide range of horsepower configurations, these are used in industrial and commercial applications such as HVAC systems, pumps, appliances, blowers and more.

Do You Know About Permanent Magnet DC Motors (PMDC Motor)?
The working principle of a DC motor is based on the premise that  when a current carrying  conductor is placed inside a magnetic field, there will be mechanical force experienced by that conductor.  The magnetic field is established by using a magnet.  Depending on the type of magnet used, it may be an electromagnet or a permanent magnet.

Worldwide Electric Motors are Worth Considering 

When you are thinking of replacing your old commercial motor, consider a Worldwide Electric Motor. At IER Services, we're excited to be partnering with Worldwide, to provide our customers reliable and affordable equipment quickly. The Worldwide brand has been trusted for over 20 years.