|Rav Yair Meir|
| A. The ProblemB. The Prohibitions Involved
C. The Halachic Status of the Invalid
D. The Suggested Solution
1. The Grama Switch
2. Spring Return
3. Modulating the Current
4. Minimum Current
5. Changing the Duty Cycle
A. The Problem
In recent years, the use of wheelchairs with electric motors has become common. These wheelchairs use a storage battery similar to that found in automobiles, which is charged by connecting it to ordinary house current for several hours when the wheelchair is not in use. The chair is operated by means of a joystick, which controls both steering and acceleration.
The wheelchair permits a high degree of mobility for wheelchair-bound invalids who cannot operate a regular wheelchair, both in the house and outside. The invalid is able to feel independent and self-sufficient, which is extremely important for his self-esteem.
Two outstanding Torah authorities in Jerusalem approached the Zomet Institute in order to devise the technical solutions to permit use of wheelchairs on Shabbat.
B. The Prohibitions Involved
Use of an electric motor on Shabbat, which does not result in the creation of light or any other Shabbat creation, is the subject of a continuing discussion among scholars. In our case, where the source of the current is a battery, the problem of power generated on Shabbat does not exist. The battery is not a
generator, and only releases power stored before Shabbat when it was charged. There are three possible categories of Shabbat prohibition that apply: