7. Universal Motor EN
These earlier Noris series of some models (Noris Record L100 (serial number < 5xxxxx), Noris Exclusiv 1000, Noris Record L) have a motor type that is somewhat exotic today. With a small modification they can still be used, though they only run at 8 fps—enough for scanning, but rewinding may require some patience.
There are four ways to identify these old models, even from photos:
- Almost certain: Silver instead of black push buttons (only one exception seen so far)
- Certain: The serial number (from 5xxxxx onwards is "new"). Found on the type plate on the bottom of the projector.
- Certain: These two screws on the underside.
- Certain: Orientation of the transformer winding, visible through the ventilation slots on the narrow rear side (Horizontal: old model, Vertical: new model)
To convert a projector with such a (notably "open-wound") universal motor, you need a 36 V power supply instead of 24 V (e.g. this one) and a bridge rectifier rated for at least 5 A and 100 V—more headroom is fine. This one is generously sized, but any other works too.
The original transformer in these old models must be disabled or removed entirely. It is an autotransformer without galvanic isolation, which can quickly become dangerous. Remove it!
The four motor leads are then connected as follows:
The schematic looks more complicated than it is — so here's a photo:
The blue and white wires from the motor (the "field winding") go to the ~ terminals of the bridge rectifier; the black and red wires (the "rotor winding") go to + and −. The leads to the "Motor" terminal of the controller board (going downward in the photo) are also connected to ~.
Only in this way will the universal motor start, and only in this way can the direction be reversed.
It's easier and faster with a DC motor, but improvising can be fun too. :)