Nova 57080 Manuel d'utilisation et d'entretien télécharger pdf (Page 21)

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Turning Tips

The Nova DVR Drive technology is not just a variable speed motor - its smart motor technology takes turning to

a new level. The speed, vibration and load sensing, work with the conditions and turning. The machine will

reward skilled turning with exceptional finish conditions. There is often no need for sanding. As you apply load

(chisel pressure or depth of cut) the control will sense the change in spindle conditions and compensate

accordingly. Get a feel of the communication between yourself and the motor turning by applying increasing

force. The motor will respond by applying increased power to exactly maintain speed.

LOW SPEEDS 100-350: Select Hard Mode (see Special and Parameter settings)

Note – at low speeds 100- 350 rpm control of the chisel is important. At 250 rpm the motor still has good torque

(in fact the torque is more or less the same as at 400 or 1000 – but at low speeds there is a difference , the

DVR is a unique type of motor in that the control only supplies enough power to maintain the spindle at the

commanded speed. It needs to sense the load from the chisel and then it will apply power as needed. At very

low speeds the chisel can move fast compared with the rotation of the wood. The important thing is to have

good control of the chisel and maintain steady cuts (using the same woodturning practices that produce quality

cuts and finishes). In this way surprisingly heavy cuts can be achieved. However, rapid or incautious use of the

chisel will be immediately sensed by machine and spindle will shut down and then automatically try a restart.

“Will The Machine Shut Down on Interrupted Cuts?”

No, as long as the cut is within the normal range of Woodturning cuts. An interrupted cut at slow rpm may

cause a loss of control of the chisel and a dig in may occur.

A way to understand chisel feed rates is to consider that at 100 rpm, the work piece has only rotated about 1

and a half turns in one second and at 250 rpm, 4 turns. Considering that chisel feed or movement under

normal turning can be anything between say 5 and 100mm per second at normal Woodturning turning speeds.

At very low rpms it is easy to move the chisel too fast for good cutting conditions. In general, low rpm is only

used for special processes or conditions. Speeds below 350 are generally not Woodturning speeds. The

machine will operate down to 100 rpm but this is generally for applying finishes and other applications.

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Nova 57080 Manuel d'utilisation et d'entretien Page 21