Controlling the RPM of a DF64 with a VFD
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Moderator's note: split from Hacking the DF64 exit chute
I have used df64 with VFD. i use panasonic VF0 series 0.75 kw. it also has low rpm torque boost feature. i can drop the rpm up to 650 rpm reliably with out stalling.spopinski wrote:Haven't found a single phase VFD anywhere.. For speed controller your grinder will lose so much torque it will stall often.
i found this VFD second hand. and it cost about 50$ US.GDM528 wrote:LOL - good catch!
How about a crappy motor speed controller with dubious specifications. I found one on Amazon - one of its specifications listed was the color: "blue"...
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Nice find! Can you post the manufacturer's model number?ltanzil wrote:I have used df64 with VFD. i use panasonic VF0 series 0.75 kw. it also has low rpm torque boost feature. i can drop the rpm up to 650 rpm reliably with out stalling.
i found this VFD second hand. and it cost about 50$ US.
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Speaking of 650 rpm, is that the speed you've settled on? I'm researching a DIY speed reducer, and dropping from 60Hz to 30Hz would dramatically simplify the circuit design.
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My unit type Panasonic Vf0 BFV0072GK-E
since i live in indonesia this unit is 220v and my df64 is also 220v
if you unit is 110v the better option is Invertek 110v single phase
https://www.invertekdrives.com/variable ... e/features
https://www.invertekdrives.com/variable ... 70-1F12-01
it is available new for about 300$
https://www.wolfautomation.com/ac-drive ... v-1-phase/
a slightly older model available second hand for 198$ at ebay
https://www.ebay.com/itm/353606261529?m ... media=COPY
Still a lot cheaper than lagom p64
one caveat though. you have to bypass the df64 control pcd and switch. it does not like high frequency switching. so wire direct motor to vfd.
most of the time i settled at 700 hz. that is about 25hz, since my base frequency is 50hz. halving the rpm from stock 1480 rpm give higher clarity in my experience. i am still playing around with the rpm because i just changed my burr to ssp Lab sweet.
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Nice find! I also lives in Indonesia and very intrigued
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you can find it here if you are in indonesia
https://tokopedia.link/Iy4bGIWqmrb
it is about 50 usd while it last
https://tokopedia.link/Iy4bGIWqmrb
it is about 50 usd while it last
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ltanzil wrote:
one caveat though. you have to bypass the df64 control pcd and switch. it does not like high frequency switching. so wire direct motor to vfd.
Interesting... I would have figured the external VFD already has a motor start function built in, making the start circuit built into the DF64 redundant.
So this is a know-what-you're-doing sort of hack, given the voltages and currents involved.
Dunno if this warrants a new thread, but I wonder if it might be simpler to swap in a different motor...
- Paul_Pratt
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I use Invertek VFD's on old 3ph grinders. I can highly recommend them. Very easy to set up.
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Do you also bypass the capacitor and use all 3 output wires to drive the motor? Effectively remove all the grinder electronics?ltanzil wrote:you can find it here if you are in indonesia
https://tokopedia.link/Iy4bGIWqmrb
it is about 50 usd while it last
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Definitely, yes IMHO, the use of a VFD will generate a lot of new field to explore, with the DF64, and even many comments, i hope, if not in a dedicate thread we could possibly lost useful shared info lost in others gigantic threads.GDM528 wrote:Dunno if this warrants a new thread, but I wonder if it might be simpler to swap in a different motor...
Swap in a different motor does not seems to me a "simpler" solution, unless i misunderstood your comment.
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i agree with giampiero. swapping the motor is ten times more hassle. i have thought of it. the motor shaft is directly attached to the burr. and stator is press to the grinder body. it is going to be a nightmare.GDM528 wrote: Interesting... I would have figured the external VFD already has a motor start function built in, making the start circuit built into the DF64 redundant.
So this is a know-what-you're-doing sort of hack, given the voltages and currents involved.
Dunno if this warrants a new thread, but I wonder if it might be simpler to swap in a different motor...
the PcB inside df64 is just a glorify relay timer that cut power after 45 second and profiding latching for the power switch.
does not protect the motor what so ever. it does not even have a fuse. it also doing nothing when the motor
start.
the vfd is way more advanced in starting, controlling and protecting the motor. it also can start the motor gently and ramping up to the dersired rpm
bypassing the PCB is very straightforward. connect two wire that come out from the motor directly to two wire from power cord. leave ground wire from the powercord connected to the grinder body. that's it. leave the big white capacitor. i will take picture of my connection
the know how part is actually more on the programing the vfd. that is the true challenge.
another thing that i might consider is actually rewinding the motor to 3 phase if desired more torque. it is also a nightmare slightly less though compared to swapping motor