Operator’s manual for the Pentruder MD1 Modular Drill System with MDU9 Modular Drive Unit - Original instructions
Page 35
5.2.3
Changing gear - Spindle with Spindle Unit ST3 and MG41 Gearbox and different sizes of
drill bits
Change gear/speed on the MDU9 Drive unit with the M-Dial. The suitable spindle speed varies
with the drill bit, type of concrete and amount of rebar.
There are totally 29 electronic gears on the MDU9 Drive Unit – NTGRA. Combined with the 4-
gears on the MG41 Gearbox there is a very wide spindle speed range available.
Note!
The spindle speed can be adjusted up and down during drilling. For optimal performance, try
different spindle speeds until the core bit cuts well and the drilling goes fast and smooth without
vibrations. A high spindle speed and peripheral speed can often be very efficient but it is
important not to use too high feed power in steel.
Note!
The output power of the MDU9 Drive Unit - NTGRA
®
varies with the motor rpm. Take care to
study the charts on page 49 and page 50 before starting to drill.
Note!
When in 1-phase mode, never directly start the spindle in speed position 11 or higher. Set the M-
dial to position 10 and let the motor accelerate up to speed. Then set the desired spindle speed.
This procedure will avoid weakened automatic fuses from tripping. Some automatic fuses have
these problems, some don’t.
Gear change MG41 Gearbox
Switch off the MDU9 Drive unit with the motor On/Off button. Disconnect
the cable to the MDU9 Drive Unit to prevent unforeseen movements.
1.
Push and turn the gear shift knob on the MG41 to desired gear
position. To make the gear engagement dogs mesh, turn the drill
bit at the same time as the index knob is turned.
2.
Connect the cable again and start the MDU9 Drive Unit.
!
Important!
•
Make sure the gear change knob is in the correct position before drilling
is commenced. The gear position number should be aligned with the
spot adjacent to the knob on the gearbox casing. Should drilling be
started with the gear in the wrong position, the gearbox may be
damaged.
WARNING!
•
To avoid uncontrolled movement of the drill bit or carriage, always
disconnect the cable to the MDU9 drive unit before changing drill bit.
Gear shift knob
M-Dial
Motor ON/OFF
push button