What sizers power belt for PM1340

[chiroone]

I understand the tri-power belt is about the best to use for the PM 1340 GT. What size should I order?

 

[Kiwi Canuck]

size BX24 and size BX25

I got mine from here.

Gates BX25 Belt

Tri-Power Notched Belt BX Section - Price: $10.68; Width: 5/8"; Length: 28"; SKU: 9013-2025

www.biedlers-belts.com

David

 

[mksj]

Flip the motor pulley and run it as a single belt speed, it would take a Gates Tri-Power BX-26 belt. If one is using a non-VFD PM-1340GT and wants to retain a 2 speed pulley drive one needs a BX-24 and a BX25 belt, the stock belt is somewhere in between those two.

When running off of a VFD If you want quicker stops, set a higher mechanical RPM drive setting and turn down the VFD Hz. So for threading I usually run my VFD at around 20-30 Hz. There is less mechanical momentum in the drive system.

Using a VFD and flipping the motor pulley, use a BX-26 (If I recall a few people have also used a BX-27):

Stock non-VFD would need a BX-24 and BX-25:

 

[Kiwi Canuck]

Flip the motor pulley and run it as a single belt speed, it would take a Gates Tri-Power BX-26 belt. If one is using a non-VFD PM-1340GT and wants to retain a 2 speed pulley drive one needs a BX-24 and a BX25 belt, the stock belt is somewhere in between those two.

When running off of a VFD If you want quicker stops, set a higher mechanical RPM drive setting and turn down the VFD Hz. So for threading I usually run my VFD at around 20-30 Hz. There is less mechanical momentum in the drive system.

Using a VFD and flipping the motor pulley, use a BX-26 (If I recall a few people have also used a BX-27):
View attachment 320663

Stock non-VFD would need a BX-24 and BX-25:
View attachment 320664

I guess I'll flip the pulley and order a new BX26 belt, somehow every time I read one of Mark Jacobs or David Bests posts I learn something new.

Thanks for the info.

David.

 

[chiroone]

OK, I got myself the BX 26 belt. What is the advantage of flipping the pulley around?

 

[mksj]

No pulley changes for low and high speed. The stock large motor pulley to large headstock pulley splits the difference between the pulley ratios, so with a VFD running to 20-90/100 Hz should give you a spindle speed range of 50-2000 RPM using the gearbox ratios/VFD. When running an inverter style motor which goes to 120-125 Hz, using a ~2.3" pulley you get about the same speed range with more optimal motor performance in the constant Hp range.

 

[Christianstark]

No pulley changes for low and high speed. The stock large motor pulley to large headstock pulley splits the difference between the pulley ratios, so with a VFD running to 20-90/100 Hz should give you a spindle speed range of 50-2000 RPM using the gearbox ratios/VFD. When running an inverter style motor which goes to 120-125 Hz, using a ~2.3" pulley you get about the same speed range with more optimal motor performance in the constant Hp range.

Mark,

Do you have a thread that dives into this? I am trying to decide what direction to go with for my now on its way 1340GT 3 Phase.

Thanks!

 

[Tipton1965]

somehow every time I read one of Mark Jacobs or David Bests posts I learn something new.

I learn that my wallet gets lighter after reading their posts.

 

[Christianstark]

I learn that my wallet gets lighter after reading their posts.

No truer words...

 

[davidpbest]

Mark,

Do you have a thread that dives into this? I am trying to decide what direction to go with for my now on its way 1340GT 3 Phase.

Thanks!

Perhaps this will help you - especially if you're considering a VFD configuration. I have posted speed tests of my PM-1340GT here using Mark's control package with Hitachi VFD. The first photo describes the motor/belt/pulley setup. The videos that follow illustrate the range of speeds available in Low/Low and High/High gear settings, along with the actual RPM with the VFD at 60Hz in each of the six possible gear settings. With this setup I am able to achieve 24 to 2081 RPM with a single belt position. And with the JOG function, I have sufficient torque to run a 5/8-11 tap (in a tailstock-mounted tap holder) into 304 stainless at 24 RPM using the Jog joystick for control (I haven't tried anything larger - yet).