- Training & Events
- Buyer's Guide
I am anxious to learn more about electric motor lubrication in the industrial environment, because very few of the electric motors in automobiles require periodic maintenance. Most have sealed bearing or bushings, which almost never require attention. However, most electric motors fail due to the eventual failure of these “permanently” lubricated bearing points.
Newer model cars have an increasing number of electric motors. Electrical devices are appearing in every car subsystem. Any part that worked manually, by hydraulics, or by vacuum in a car 60 years ago has now been replaced by an electrical device. To my knowledge, the first electrical motor on a car was the electric starter. It replaced the old hand crank, which could break an arm if the timing and the throttle weren’t set just right. The first electric starter appeared in a 1912 Cadillac or a 1912 Inter State, depending on which claim you believe. Check out the reference section for a link to read the complete story.
We must define the term motor as it differs between devices. For the purpose of this article, an electric motor is defined as a rotating electrical component that performs work as it derives its power from the battery/generator system of the car. Note that a solenoid that merely pushes or pulls when a current is applied to its magnetic windings cannot be classified as a motor in this discussion. A solenoid performs work, which is part of the definition of a motor, but in this discussion it does not rotate and is not to be called a motor.
In my column in the January 2002 issue entitled “42 - Gallons, Life and Volts” I wrote the following:
In the late 1960s, a car with power accessories (such as windows, seats or air-conditioning) seldom demanded more than 500 watts from the electrical system. These 12-volt times 50-amp systems were adequate. However, electrical cooling fans, high-volume stereo systems, antilock brakes and computer-controlled emission systems have recently been added. Vehicle loads are expected to exceed 2.5 to 3.0 kilowatts soon. With 42 volts, more power can be transferred with smaller wires, connectors and cables, which will reduce the space demands under an already crowded dashboard and hood. 36-volt batteries and 42-volt generators which keep them charged are manufactured today for 2004 models. Visit www.delphiauto.com for more details.
For fun, I counted the electrical motors in a 1997 Buick Park Avenue, which happens to be the car my wife drives. Granted, the Park Avenue comes equipped with most of the options a GM car of that year would offer. Not all options though … no sunroof. The exercise was to estimate how fast this electrical invasion is evolving. There are 37 different electrical motors in her car! I was surprised at this number, and was not aware there were so many electric motors until I sat down and looked at all the systems on the car. How many motors are in your car? E-mail me your car details and I will tell you (firstname.lastname@example.org).
It is interesting to note that the first manual wiper was invented in 1903 by a woman named Mary Anderson. A few years later, Charlotte Bridgewood patented the first electric windshield wiper (1917). The early-model vacuum wipers worked well until the car sped up to pass another, and the wipers would almost stop. Electric wipers were quickly accepted as an improvement over such inconvenience.
Electric Cars Abuzz
The dawn of practical electric cars is here. In 2004, both Toyota and Honda are making a hybrid gas/electric car. It’s impressive that these manufacturers use the electric motors to brake the car and recover the kinetic energy to recharge the batteries. Before such advancement, the energy was sloughed off in the heat generated by brake components and wasted. These cars use a small gasoline motor to cruise on the highway and to keep the batteries charged for the primary motor, an electric motor. Electric motors are most efficient under acceleration, and gasoline engines are not.
While the opposite is true, that electric motors are not efficient at cruising speeds, that is when gasoline engines perform their best. The pollution levels for these cars are amazingly low. Toyota and Honda sell a comfortable car for four, with some accessories for around $22,000. They have a rating of about 50 mpg - a worthwhile consideration in these times of high gasoline prices. If you drive less than 50 miles a day to work, you would save a bundle on gas. As an incentive, there is a nice tax deduction (about $3,000) from the Internal Revenue Service for such a purchase. The Big Three American automakers are planning to offer the same sort of car soon.
I drive the same six miles to work and back every day, and then another 20 miles running errands to the post office, bank and grocery store. For a while, I considered electrifying my Chevy S10 pickup for this daily route. If the auto manufacturers make a small pickup with the hybrid set up soon, I may be in the market. I would, however, miss the throaty roar of a V-8 twin exhaust with open mufflers.
With cars’ electrical accessories load approaching three kilowatts and electrical motors with their zero pollution rates, we will see an increasing number of electric motors on cars for years to come. They are quiet, easier to control in incremental adjustments and can be made amazingly small. For example there are seven electrical motors in the 8-way power seats of the 1997 Buick Park Avenue. They are tiny but powerful. The motors are even showing up in new places like powered adjustable mirrors because they can be made so small. For example, there are two motors in each of the outside rearview mirrors.
Compact Yet Efficient
In a previous article, “Drip Drop” (November 2003), I described how I found vacuum leaks in the traditional vacuum-operated air doors of the HVAC system inside a car’s dashboard. Electric motors require less space. An electric motor that measures 1 by 2 inches can replace the vacuum diaphragm - about 3 inches - the actuating arm which can take another 3 inches of space to travel. Vacuum hoses are larger and more susceptible to damage than insulated wires.
Not much to be lubricated here. Whereas you might find a few 200 HP electric motors in a plant, the starter is the only electric car motor larger than 1 HP. Most of the motors mentioned in this article are less than ¼ HP. We can, however, lubricate the power transmission supply lines in our car’s electrical system. We should also keep the battery terminals clean and charge the battery if it gets discharged. It is important not put the strain of recharging a dead battery upon the alternator. This would strain the alternator, and replacing it can often cost more than $200. Have your mechanic check the major ground connections about every 50,000 miles. If your mechanic balks at this idea, find one who knows about electricity. With more and more electrical devices connected to the alternator/battery systems, this will become increasingly critical in the future.