833 motor

parshal said:
I have a TV and I've not been disappointed in low end torque. I do more than aluminum. Personally, I love the ability to drill and power tap without changing anything other than the bit. The way I use the mill I'd be changing gears too much with the T.
Click to expand...
How are you power tapping with the 833TV?
 
I'm not sure I understand the question. I drill a hole, chamfer it and tap at a very low speed.
 
parshal said:
I'm not sure I understand the question. I drill a hole, chamfer it and tap at a very low speed.
Click to expand...
Good to know. I do a lot of power tapping on my large drill press. I assumed the 833tv won’t have the torque required at low speed. I just got my 833tv set up and will try some power tapping to see how it performs.
 
I normally tap small holes, nothing even 1/4", and I've managed to break more than one so the torque is there. I don't tap steel often though.
 
Kev-in said:
Good to know. I do a lot of power tapping on my large drill press. I assumed the 833tv won’t have the torque required at low speed. I just got my 833tv set up and will try some power tapping to see how it performs.
Click to expand...
I have an 833TV and I frequently use it for power tapping. It will handle 1/2"-13 threads in mild steel providing some conditions are met. First, torque seems to be related to spindle speed. At the lowest end of the machine's speed range (60 rpm +/-), torque drops off significantly. I find that at around 120-130 rpm, the machine has significantly more torque and I'm still able to control things. 2nd is using a high-quality, sharp tap. This video
demonstrates the different torque requirements for several brands of new taps under the same conditions. A good quality spiral flute tap generally works best...even when threading through holes. 3rd is liberal use of a good cutting fluid.

If you plan on power tapping holes larger than 1/2" in steel, the 833TV is probably not the best machine choice.
 
MLab said:
I have an 833TV and I frequently use it for power tapping. It will handle 1/2"-13 threads in mild steel providing some conditions are met. First, torque seems to be related to spindle speed. At the lowest end of the machine's speed range (60 rpm +/-), torque drops off significantly. I find that at around 120-130 rpm, the machine has significantly more torque and I'm still able to control things. 2nd is using a high-quality, sharp tap. This video
demonstrates the different torque requirements for several brands of new taps under the same conditions. A good quality spiral flute tap generally works best...even when threading through holes. 3rd is liberal use of a good cutting fluid.

If you plan on power tapping holes larger than 1/2" in steel, the 833TV is probably not the best machine choice.
Click to expand...
This correlates well with this test. It is also another correlation to the analysis I did in this published document (pages 10-11). It's a testament to the limits of running that motor at below 10 Hz. From the referenced document:

PM833TV.jpg
 
Kev-in said:
Good to know. I do a lot of power tapping on my large drill press. I assumed the 833tv won’t have the torque required at low speed. I just got my 833tv set up and will try some power tapping to see how it perfored
Click to expand...

sry David beat me to it
 
dabear3428 said:
are we talking about power or torque because a vfd driven motor has 100% of rated torque almost at 0 rpm. not really but close.
Click to expand...
HP, not torque. David's chart correlates well with my observations. At low RPM, there is very little power available to drive a tap or large drill.
 
dabear3428 said:
are we talking about power or torque because a vfd driven motor has 100% of rated torque almost at 0 rpm. not really but close.
Click to expand...
Your “not really” applies here. At 50 RPM the 833TV motor is being driven at something like 3-5 Hz. This is clearly below the nominal torque range of the motor. One might argue this torque range could be broadened with a vector drive motor and tuned VFD. Unlikely that’s what is in the 833TV.

IMG_2452.jpeg


But the truth is in these real world tests. I’m not surprised the torque improves measurably at 120-130 RPM - which would be more like 10-15 Hz.
 
You must log in or register to reply here.
Back
Top