Round Ram Upgrade

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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spro
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Re: Round Ram Upgrade

Post by spro » Tue Feb 19, 2019 12:17 am

Looks like your are doing a fine rebuild. I thought the round rams were near solid, even though, the V rams had the same tongue at the back. Since both sides allow a head to be tilted L-R by either the adapter or your solid one, there may be another way to use the ram slot. In that case, a section of "rack" inside the slot. The teeth wouldn't protrude beyond the circumference and assist careful extension/ retraction of the ram.

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whisperfan
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Re: Round Ram Upgrade

Post by whisperfan » Fri Feb 22, 2019 8:13 pm

It's back together - I dind't repaint the head ... but it falls into the 'close enough' category for now.

Image

Image

Image

It's not perfect, but it is a heck of a lot better than when I started.

spro
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Re: Round Ram Upgrade

Post by spro » Sat Feb 23, 2019 12:09 am

Sure it is. Hey you got the pancake motor too ! This is going to be great. I think you need get your phases right by use of capacitors' balance. There is lots of info about that. I wouldn't care but those old motors( super long shaft and not top heavy ) are getting ....

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whisperfan
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Re: Round Ram Upgrade

Post by whisperfan » Sat Feb 23, 2019 6:12 am

spro wrote:
Sat Feb 23, 2019 12:09 am
Sure it is. Hey you got the pancake motor too ! This is going to be great. I think you need get your phases right by use of capacitors' balance. There is lots of info about that. I wouldn't care but those old motors( super long shaft and not top heavy ) are getting ....
I want to look into that ... but from my research, if I power L1 and L3 from my panel ... and use my 5 HP 3-ph motor to supply the 'ghost leg' of the missing 3-ph power even if I balance the power output using capacitors .... I will have 'balanced' three phase power as you look at it with a meter .... but the phases still won't be 'right'. In three phase power, when looked at through an oscilloscope and not a multi-meter the three peaks of the sine waves are 120 degrees apart and the voltage is balanced. But since I would be supplying two legs from a 1-phase power source and those sine waves are 180 degrees out of phase, then my capacitor-enabled phase converter would balance the power, but not the degrees out of phase that the machine runs.

I agree that balancing the voltage will help, but I don't know to what degree the degrees out of phase impacts the heat, hp, and lifespan of either the idler motor or the machine's motor.

I was in aviation electronics in the Marine Corps and I haven't thought about transistor thearoy, capacitors, and resistance for a long time! :D
After all, not much call for air-to-air RADAR guided missiles in civilian life

Milling along
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Re: Round Ram Upgrade

Post by Milling along » Sat Feb 23, 2019 10:17 am

These days I would not fool with a rotary converter. At best they were never perfect in re-creating
correct 3 phase power. The phase angle and flying lead voltage would vary depending on the load
on the motor. The voltage on the flying lead could get very high if not properly balanced.

VFD's are so cheap that there is no reason to not use them. They have a lot of bonuses like variable
speed, soft start, come in their own electrical box, and most have a display showing speed. But remember
that there should be no switch or fuses between the motor and the VFD. They should be directly connected
together. That pretty much means that you need 1 VFD per 3 phase machine.

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whisperfan
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Re: Round Ram Upgrade

Post by whisperfan » Sat Feb 23, 2019 12:51 pm

A lot to think about on this topic. Thanks for the heads up on VFDs

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NP317
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Re: Round Ram Upgrade

Post by NP317 » Sat Feb 23, 2019 2:02 pm

I would also use a VFD.

When we restored the two Seattle Center Monorail Trains for their 50th birthday in 2012, we had to consider how to produce the various required Voltages needed, and operate the motor-driven accessories.
Traction motors used the 600Vdc from the power rails along the beams.
There were 24V battery packs used to derive 24 Vdc, 12Vdc, and 5 Vdc, used for the various control systems. Batteries charged from the 600 Vac.
A solid state 600V DC to 120AC converter 1-phase for the train lights. That replaced the old motor driven DC to AC converter. Vibration had been a constant issue.
Motor-powered air compressors for brakes and doors got power from the 600 Vdc, feeding VFDs to provide 3-phase power for those compressor motors.
Those VFDs were a lifesaver, both from a design and functionality perspective. Reliable.
Both Monorail Trains continue to operate today with better-than-new reliability.

Use VFDs for your machines. My milling machine does that, and provides variable rpm, as a result.
Delightful to use.
~RN

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whisperfan
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Re: Round Ram Upgrade

Post by whisperfan » Sat Feb 23, 2019 5:43 pm

I'll really need to look into it ... my dilemma is that I use my mill rather infrequently, but I also have a surface grinder. To re-work the rotary converter I already have will be cheaper than two VFD's - I also think that sometime in the future I will end up with a 3-ph lathe, my current one is single phase.

If I used all my machines more than I do, then getting a VFD for each would make perfect sense - but I have to consider costs vs. benefits. While VFD's are really nice, I think that I may just re-work the rotary converter. Rather than doing a bunch of wiring I found a control panel box that has all the wiring done, and it replaces my 1-ph 'kicker motor' with a start capacitor (That would be nice) The company I am looking at seems to have some good reviews too

dly31
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Re: Round Ram Upgrade

Post by dly31 » Mon Feb 25, 2019 12:13 am

whisperfan wrote:
Sat Feb 23, 2019 6:12 am
spro wrote:
Sat Feb 23, 2019 12:09 am
Sure it is. Hey you got the pancake motor too ! This is going to be great. I think you need get your phases right by use of capacitors' balance. There is lots of info about that. I wouldn't care but those old motors( super long shaft and not top heavy ) are getting ....
I want to look into that ... but from my research, if I power L1 and L3 from my panel ... and use my 5 HP 3-ph motor to supply the 'ghost leg' of the missing 3-ph power even if I balance the power output using capacitors .... I will have 'balanced' three phase power as you look at it with a meter .... but the phases still won't be 'right'. In three phase power, when looked at through an oscilloscope and not a multi-meter the three peaks of the sine waves are 120 degrees apart and the voltage is balanced. But since I would be supplying two legs from a 1-phase power source and those sine waves are 180 degrees out of phase, then my capacitor-enabled phase converter would balance the power, but not the degrees out of phase that the machine runs.

I agree that balancing the voltage will help, but I don't know to what degree the degrees out of phase impacts the heat, hp, and lifespan of either the idler motor or the machine's motor.

I was in aviation electronics in the Marine Corps and I haven't thought about transistor thearoy, capacitors, and resistance for a long time! :D
After all, not much call for air-to-air RADAR guided missiles in civilian life
Actually, if the voltages are all equal in a three phase system the phases have to be equal also. Try drawing a triangle with three equal sides (voltages) and the angles (Phases) unequal. The three phases are best understood when diagrammed as a delta although a wye diagram also works. We generally measure the voltages phase-to-phase.
Don Young

Milling along
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Re: Round Ram Upgrade

Post by Milling along » Mon Feb 25, 2019 12:46 am

Three phase power can get complicated when it is not an exactly balanced Y system. By a balanced Y system I mean
that each phase is at the same voltage and that the center of the Y is at zero volts. A complication comes up with a
rotary phase converter. That is that the two driven phases are connected to the split phase 120/240 volt system that
most people have. The third (flying) phase is produced by the rotating magnetic structure of the converter motor.
This flying phase should be corrected as best as possible using capacitors. So far so good.

However this system results in the center of the Y not being at ground potential. The ground potential is at the center
of the two driven phases. For a delta load there will be no problem. But for a Y load you must not connect the
center of the Y to ground. It will be about 70 volts from ground (as I remember).

This can make measuring the voltages of such a system a little confusing. If you measure from phase to phase
you will get correct readings. If you measure the phase voltages to ground you will get some odd readings
until you understand that the center of the system is not at ground.

Also the insulation in the motors will be stressed unevenly. The flying lead will be at 190 volts (120 + 70)
with respect to the motor frame. On modern motors this should not be a problem, the insulation is quite good.
On old motors this could be a problem; the insulation may have degraded with time and may not have been that
good to begin with.

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whisperfan
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Re: Round Ram Upgrade

Post by whisperfan » Tue Feb 26, 2019 11:02 am

To me - it matters what you do with the areas - parts that no one sees or doesn't see too often! :)

Image

Image

Image

I made a couple shelf boards from red oak and put a few coats of polyurethane on them - near too nice to close the door!

spro
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Re: Round Ram Upgrade

Post by spro » Mon Mar 04, 2019 6:33 pm

This is really nice fitment of oak. They have to be good because there is a lot of weight to be put there.

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