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Q. What is the difference between radial and pantograph wiper systems?
A. Radial wiper systems are typical to most automotive applications. They use a single arm that sweeps the blade in an arc pattern. Pantograph wiper systems have a double arm. One arm is a drive arm that attaches to the pivot shaft; the other is an idler arm that pivots off of a post called a pantograph adapter and keeps the blade parallel to the side edge of the glass (or the center mall, in a split windshield).

Q. How do I choose which pattern is best for my application?
A. Generally, glass that is wider than it is tall is wiped better with a radial pattern; pantograph patterns work better on tall, narrow glass. Usually, the pivot locations are close to the window for radial applications and farther away for pantograph applications.

Q. How do I know which wiper motor to use?
A. Wiper motors are rated by stall torque. This is usually expressed in Newton meters (Nm) (See conversion table on in Reference Info.). For arm and blade combinations 28" and longer, and for multiple arms and blades driven by one motor, a 38Nm motor is recommended. For arms and blades in the 20" to 28" range, a 30Nm motor is suitable. For arms and blades in the 16" to 20" range, a 12 Nm motor is appropriate. For small arm and blade combinations, 16" and under, often an 8Nm to 10Nm motor works well. Often motors of 20Nm or less have internal linkage to make the necessary oscillating motion.

Q. What is the difference between coast-to-park and dynamic park motors?
A. After they are turned off by a switch, motors with an automatic park feature will continue to run until they reach their predetermined park position at one end of the sweep pattern or the other. They will then shut themselves off. On coast-to-park motors, the power is internally disconnected and they "coast" to a stop because the motor brushes are de-energized. On dynamic park motors, when the motor reaches that assigned park position, the motor electrically locks itself in the park position. The park position is consistent each time on a dynamic park motor. The park position may vary several degrees with a coast-to-park motor. Dynamic park requires specific motors, switches, and wiring circuits.

Q. What circuit protection should I provide?
A. 12VDC motors draw about 5 amperes during normal use. With heavy snow or wind loads, this will increase. A 10 amp circuit breaker for one motor, or a 15 amp circuit breaker for a two motor system is recommended. For 24VDC motors, use a 5 amp breaker for one motor and a 7 amp breaker for two.

Q. Can I use a rocker switch, or toggle switch, for my self-parking wiper motors?
A. Yes, if you use a one-speed coast-to-park motor, or only the low-speed on a two-speed coast-to-park. Wire the park circuit "hot" through the ignition switch directly. Use a single-pole, single-throw switch to energize the low speed brush. Do not use the high speed on a two-speed motor with a toggle or rocker switch. Correctly circuited switches for two-speed and dynamic park are featured in the switch section of the catalog.

Q. What is meant by right hand or left hand park?
A. These terms were replaced by clockwise (CW) to park or counterclockwise (CCW) to park. Facing the window from outside the vehicle, see if the wiper arm and blade must travel "clockwise to park" or "counterclockwise to park."

Q. Why do wiper arms and shafts have so many interfaces (i.e. knurl drum, tapered knurl, DIN)?
A. Over the years, the mainstream manufacturers have each developed their own standards for wiper arms. Drum interfaces were popular in 1950s and 1960s automobiles. The tapered knurl is commonly found on many off road applications, as well as larger applications such as motorhomes and busses. The European DIN standard is the latest world wide adopted interface and can be found on all types of equipment