Page 2 of 4
Re: DIY DVR motor upgrade / replacement
Posted: Sat Feb 01, 2020 4:02 pm
by CNC4FUN
I am also thinking to switch to timing belt.
If anybody have an advice on selecting pulley and belt size I will appreciate it.

- 20200201_153912.jpg (55.06 KiB) Viewed 9830 times
Sent from my LG-H872 using Tapatalk
Re: DIY DVR motor upgrade / replacement
Posted: Sat Feb 01, 2020 9:02 pm
by lahola1
Your conversion looks real good so far. I don't know much about timing belts.
What speed range do you expect to get with the timing belt?
I'd sure hate to lose the 3 pulley/ belt system on mine.
It's just so easy move the belt on the pulleys (only takes about 45 seconds)
to keep the dc motor more in the 15%- 85% speed range where it works best.
Re: DIY DVR motor upgrade / replacement
Posted: Sat Feb 01, 2020 9:36 pm
by CNC4FUN
DVR motor will run from 50 to 5500 RPM and I will not need to change belt position.
Speed is easely adjusted from control panel.
Pulleys can be identical. (1:1 ratio)
Sent from my LG-H872 using Tapatalk
Re: DIY DVR motor upgrade / replacement
Posted: Sat Feb 01, 2020 9:37 pm
by CNC4FUN
Distance between shafts is approx 7.4"
Sent from my LG-H872 using Tapatalk
Re: DIY DVR motor upgrade / replacement
Posted: Sat Feb 01, 2020 9:54 pm
by thunderbirdbat
Here is a calculator for belt length or pulley size. Hope it helps.
https://www.blocklayer.com/pulley-belteng.aspx
Re: DIY DVR motor upgrade / replacement
Posted: Sun Feb 02, 2020 6:14 am
by reible
What is the plan for belt adjustments?
Ed
Re: DIY DVR motor upgrade / replacement
Posted: Sun Feb 02, 2020 8:38 am
by CNC4FUN
There will be only one belt position.
Speed is digitally controlled.
As it is now, motor sits all the way up against housing. It can slide only down, away from power takeoff pulley.
I am guessing that this will be enough to tension the belt. I will need to cut longer slot on the right hand side of mounting plate.
Sent from my LG-H872 using Tapatalk
Re: DIY DVR motor upgrade / replacement
Posted: Sun Feb 02, 2020 12:42 pm
by JPG
Since timing(cogged/gilmer) belt is being used, tension is not critical.
Re: DIY DVR motor upgrade / replacement
Posted: Sun Feb 02, 2020 3:59 pm
by reible
JPG wrote:Since timing(cogged/gilmer) belt is being used, tension is not critical.
I have to disagree, while maybe not as for tension but a loose belt is very likely to strip teeth especially since there is no clutch involved. They very often employ a idler wheel that provides the tension but I don't see that happening here.
Ed
Re: DIY DVR motor upgrade / replacement
Posted: Sun Feb 02, 2020 4:06 pm
by JPG
reible wrote:JPG wrote:Since timing(cogged/gilmer) belt is being used, tension is not critical.
I have to disagree, while maybe not as for tension but a loose belt is very likely to strip teeth especially since there is no clutch involved. They very often employ a idler wheel that provides the tension but I don't see that happening here.
Ed
I chose the word critical. It IS quite NECESSARY, but not overly precise. Tight enough to not slip under load, but not so tight as to cause the cogs to bind in the pulleys.
Gilmer belt tension on a M5 is adjusted audibly. When the belt/pulley creates noise, the tension is backed off until quiet.
I do agree the lack of a clutch is risky(to the equipment).