FAQ Compressor, function and switch - Zetor UR1

[Joachim]

Zetor UR1 Compressor


Turning on the compressor
How is the compressor of the UR1 series (Zetor 2011 - Zetor 7340 Major) switched on and off?

1. Start the motor
2. Reduce the engine speed as much as possible so that it still runs
3. Switch on the compressed air compressor see photos:
   - First lift the locking lever directly on the compressor cylinder base
   - then with the engine running, very slowly, push the shift lever in near the injection pump to the compressor.
   - then release the locking lever

Here are the switching positions again in detail:


Looking into the crankcase of the compressor at the dog clutch - engaged:


Looking into the crankcase of the compressor at the dog clutch - switched off:


Sectional model / diagram


Technical data

• Bore 65 mm
• Stroke 42 mm (short stroke)
• Displacement 139 cm³
• Rated speed 1,100 rpm
• Rated output at 6 bar output 5,080 L/h (84.6 L/min)
• Operating pressure 6.1 bar
• Maximum pressure 9.1 bar
• Power consumption at 6 bar approx. 1.07 kW

History
From a design perspective, there were two notable changes to the UR1 compressor:

1. 1994 New design (B) of the compressor head (within the 3320-7340 series)
   
   What was new was the use of a disc valve for increased stability and better air throughput and cooling fins to better dissipate the heat from the head, now also on the compressor head instead of just on the compressor cylinder.
   
   
2. 1997 The on/off switch device was eliminated (with the introduction of the 3321-7341 Super series), from then on the compressor always ran when the engine was running.
   Some time ago, in some export countries, the on/off switch lever was sawn off directly before a tractor was sold and thus shut down. This should prevent you from driving an air-braked trailer with the compressor switched off and thus having no trailer brake. Since the Zetor 5211, some convenience functions have also relied on compressed air for control.