The projectors work with a combination of a resistor and lamp.
Depending on the type of resistor you can use a specific lamp. 
This is described in the user manual in detail. The lamps use base P28s.
P28s 100-120V 500W
P28s 100-120V 750W
P28s 100-120V 1000W

Film gate is totally removable so it gives you access to all areas when cleaning is needed after showing a feature.

The film pressure plate gate has a back shoe sprung gate(rear pressure plate) compared to the standard sprung gate (front pressure plate) that is found on all other makes of 16mm projectors. The advantage of having a rear pressure plate is that it can project warped or shrunken hard to run prints and keeps them in focus every time.

The 3 claw mechanism is situated on the front plate near the lens holder which works extremely well when running films with either worn or torn sprocket holes. As well as keeping the film lodged in the film gate for smooth running. ?

For maximum light output this projector has a special control knob for the selection of shutter speed operation. When operating on 16 or 18 frames per second, the 3 bladed shutter position should be used. By using 20 to 24 frames per second, the 2-bladed shutter position is selected which increases the light output even further. This function is also handy when transferring film to HD or DVD.

This machine is fitted with a stroboscope which is used to judge the correct running speed of the projector in 16,18,20,24 frames per second. The speed will remain constant no matter what size of film spool or length of operation. Additional speeds of either +/- 5% can be obtain with an option to throw single frames during projection.

An Ampere-meter is used to control the lamp circuit current which depends on the type of lamp used Either a 250volts 500,750 or 1000 watt lamps can be used.

Sound Amplification is run by a separate amplifier which can be connected to other auxiliary applications for recording or stereo reproduction from the projector if needed. This amplifier which gives out a very warm and deep sweet sound as you will only find with Siemens amplifiers of this type. There is separate bass and treble controls along with a selector for magnetic or optical sound tracks amplification. This amplifier is also equipped with the ability to record on magnetic sound film at the press of a button. You also have a built in Oscilloscope to measure the sound frequency when recording on sound magnetic film.
Specifications

REEL CAPICITY = 650m (2,200 feet). Can be extended to 4,000ft with extension arms not supplied.
THREADING = Manuel (less chance of film damage).
RUNNING SPEED = 16/18/20/24 Frames per second with additional +/- 5%.
POWER INPUT = 110/125/150/220/240V 40 to 60 Hz.
SHUTTER SPEED = 2 or 3 Blades.
AMPERE-METER = Used for monitoring light voltage.
LAMP SETTING = By turning the master switch further clockwise the screen brilliance can be increased.
LAMP ADJUSTMENT = Possible by turning the lamp adjustment control knobs to get a maximum light output.
PROJECTOR LAMP = 500/750/1000 W. (New 1000w lamp fitted)
EXCITER LAMP = BRK, 4V-0.75A.
SOUND = Can play back 16mm films with either magnetic or Optical sound track.
PILOT LAMP = To be used in low light conditions to help threading or checking film movement whilst being projected.
SCANNING ADJUSTMENT = Alignment adjustment can be made at any time on Optical prints where the sound track is not printed in the correct position by just using a coin.
LENS = Standard Astro - Kino - Color V 1:1,5 50mm plus additional lens 1:1,8 25mm lens.
SOUND TYPE = Optical sound Magnetic sound Playback & Recording possible.
AMPLIFIER = 15watts RMS output, 5 Tube amplification with separate Bass and Treble controls.
ELEVATION = Fast acting tilt control knob.
AUTOMATIC INCHING = For checking free transportation., correct loops and free movement of both reels and correct threading before use.
REWIND = High speed rewind if required by pressing the clutch lever on the take up spindle.
LUBRICATION = As the projector is self lubricating it is unnecessary to oil any part of it.
MADE IN GERMANY BERLIN - MUNCHEN (This is a genuine Siemens product)

One of our Siemens 2000 projectors has been used in this video clip: Y.V.E. 48 - All You Need (Official Music Video) by Armada Music: