forum.cncdrive.com

Hello,
a question relating to the rotation of the spindle.
the use of an RS485 makes it possible to control the speed via UCCNC. we integrate the pluggin, the minimum and maximum speed is 6000 and 24000 RPM.
In the context of drilling in wood, the average speed of a standard drill is about 600 to 1000 RPM.
Since our minimum spindle speed is 6000 RPM, it is impossible to reach a lower speed. What is the way to proceed in this case.
Finally a 2nd question always related to the speed of the spindle, our speed entered in the pluggin being 6000 and 24000 RPM, if we manually increase the speed to 300% we obtain 18000 RPM. Here also how should it be done if one wants to turn to the maximum of the capacities of the spindle without being obliged to modify the information of the pluggin?
Thanking you in advance
CDT
Patrick

Use a different spindle, or drill at 6000 rpm.

I don't understand your second question.

I am using a standard huanyang 2.2KW spindle and the goal is still to drill or mill at the correct rotation, this is the totally useless response style

the problem is not related to the spindle but to the setting of the UCCNC
my questions are translated by google

You can set the minimum speed to less than 6000 rpm, but doing so will likely destroy your spindle.

You have a spindle with a minimum speed of 6000, and you are asking how to use it at lower RPM? (I think?) The answer is you can't, without risking destroying the spindle. Unless I don't understand this question either?

For the second question. Do you want to increase the override to 400%? If so, you can do that with the screen editor, as the Override field is limited to 300% in the screen file.

thanks for your answer, actually i thought this motor could go down to slower speeds but it seems not so you have to use the right tool to work. For the 2nd question, you understood correctly, I have to go through the MDI to increase the speed
CDT

First is to make sure the VFD operating parameters are setup correctly, i.e. min and max rpm, voltage, motor amps, accel and deaccel times, etc. VFD's are not plug and play devices.

Set the start -stop and speed control to the drive front panel. Manually run the drive from min (0) and max (24000) speeds checking RPM's with a hand tach or similar device. Then reconnect the drive to the RS485 output. Repeat the same procedure to check PPM's. If it's not correct then you can change the min and max rpms in the drive or plugin. Very rarely will it a perfect match right out of the box. Minimum rpm should be 0 and max 24,000. By setting the plugin min at 6000, you've offset the speed range in the wrong direct. Basically what you need to do is set the VFD for 0-24000 and the plug in for 0-24000 so they match ranges.

As far as the motor.... The spindle motor is rated at 6000-24,000 rpms this is the usable torque curve range, 6000 is not the minimum speed but minimum torque curve. The spindle motor will NOT be destroyed running it lower than 6000 rpms, however it will stall depending on the cutter load. Without a load the motor will happily run at 100 rpms all day.

The VFD is operates in the "volts - hertz" mode which mean as the frequency is reduced, motor voltage is reduced the rpms (and torque) go down. The current is limited by the motor amp rating programmed in the drive. As the load goes up the amps follow. If the VFD motor rated amps isn't programmed correctly i.e. set too high, there is a risk of damaging the motor if it stalls, under load at zero speed for too long. Most motor are rated at 150% over current. But here again, we are dealing with china quality control.

The only way to get 600-1000 rpms to a cutter from a spindle motor is gear or belt system that keeps the spindle motor rpms' high enough within it's torque range. The other more costly option is buy a VDF with "vector mode" option. They can operate motors at 100% torque down to zero rpms. Vector VFD's are used in industrial application in the place of DC motors. But now you are looking at a $1800 - $2000 drive for 2.2kw.