Operator’s manual Pentruder
®
3P8 HF-wire saw and Pentpak - Original instructions
36
5.1.3
Facts about the automatic tension system
•
The power consumption the "feed control" or rather "power / tension system" tries to achieve is set on the
right hand potentiometer on the RCU.
•
To use all the power which is available, the control tries to maintain a tension in the wire that creates the
resistance needed to use the power requirement set on the Remote Control Unit (RCU).
•
The cutting speed is continuously variable from 0 to 22 m/second, 4330 sft/min, when driven by the 18,
(25HP) and 22 kW (30HP) motors, and up to 25m/s, 4920 sft/min for the 27 kW (37HP) motor.
•
If the required (or desired) power is set to 100%, the control tries to use all the 27, 22 or 18 kW available
from the HF-motor.
Note!
If it is a small object, with a short contact length for the wire, a setting of 100% power means that the
wire must be tensioned very hard to use all the power as very few beads are in contact with the cut object,
(which doesn’t create enough friction). This means high wire wear and risk for premature wire joint failure.
This is why the power setting should be turned down by smaller objects.
•
If the wire is working over many meters contact length with the cut object, many beads are in contact with
the cut object, and the wire tension will be less, to create the friction needed, and then the power can be
turned up to 100% and the wire life will still be good.
Note!
This means the smaller the cut object is, the harder it is to use all the power, and to achieve high
cutting rates, or cut square metres per hour.
It also means the bigger the object is, (up to a certain size, of course) the easier it is to use all the power, and
to achieve high cutting rates, or cut square metres per hour.
•
if you see slack, not enough tension in the wire, move the Joystick UPWARDS manually, some short
movements at a time, to "override" the automatic tensioning by the software.
5.1.4
Cutting of soft concrete, or concrete mixed with soft materials
Here are some tricks that can be useful in cutting soft material:
•
If you see slack, (not enough tension in the wire, please move Joystick UPWARDS manually, some short
movements at a time, to "override" the automatic tensioning which normally is done by the software.
•
To explain the same thing with other words: If you cut very soft materials, the automatic tensioning of the
wire may need some "help" from the operator, to take up excessive slack in the wire. So then you may need to
keep control of the wire tensioning manually, by moving the Joystick UPWARDS some short moments at a
time. If there is too much slack, you have a risk that the wire will jump off the wheels.
•
Use the feed potentiometer, the one to the right on the Remote Control Unit (RCU) to reduce the tension in
the wire. If you reduce down to 25% - 50%, it will still cut quickly enough in soft material.
•
Most of the time you can run full wire speed, the left hand potentiometer, in soft material, but use your
"feeling" also. After some time practising, you will get the "feel" for the machine. The first few days using
a new machine are always a bit difficult for the operator.
•
If the wire is cutting too quickly, you can have pinching of the wire, it means that the material is removed too
fast, and that the wire may jam all the time. Then you must reduce the %-age on the right hand potentiometer
on the RCU.
•
The automatic control always tries to use the power you set the potentiometer to. Please note, if you use the
22 or 27 kW kW motors, most other compact (non-quarry type) wire saws have less than half the power, so
you can reduce a lot, to below 50% and still have plenty of power available.