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glacially slow machine shop build

arse_sidewards said:
I suspect that if I have problems it will be on the cross slide or compound and not the carriage since that channel is so much further from the chips.
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You're putting one on the compound? That's going to be an absolute PITA for very little gain.
 
arse_sidewards said:
Why do you say that?

I plan on cutting a decent number of tapers with the compound.
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Dealing with a cable flopping around whenever you try to rotate the compound will be super annoying. And most of the time you're not worried about a specific depth when you're running a taper off the compound - and if you are, just make a simple stop that clamps to the compound ways or use an indicator.

Plus anything you mount there is going to take the most abuse from chips and rogue flying parts.

I've cut plenty of tapers with the compound and really cant think of a case where a dro would have bene useful.

I'm sure they exist, but I honestly can't recall ever seeing anyone use a scale on a compound....and I can't see one being more useful than annoying for normal use.


My little Atlas has one on the tailstock and there have probably only been a handful of times where it was moderately useful. Most of the time it just gets in the way.
 
Fuck it. I'm a cheapskate so I bought the 2-axis kit and will be rolling with the tape I have. Cost is ~$600.
 
bgaidan said:
If they'd be any use, I have piles of hardened square head bolts in pretty 1/4-5/8". I fish them out of the giant bin of hardware at the scrap yard and pay .25/lb for them.

1622382085870.png
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Expect a PM about this.
 
So I'm still casually looking for a motor in the 20-30hp range for a VFD. This came up. Seems kinda pricey but it is 30hp. Thoughts? Keep in mind I could make do with a motor that's a ton older and has a ton more hours on it than this one.


boston.craigslist.org

Worldwide Electric Corp 30 HP Electric Motor 3 phase - Industrial...

Worldwide Electric Corp 30 HP Electric Motor 3 phase - Industrial Explosion Proof The motor is in West Wareham MA MODEL XWWE 30-18-286T 230 V This motor was purchased from a electrical contractor...
boston.craigslist.org
 
vfd or rpc
because it sounds like you mean rpc

call around to some mobile crane companies, ask who they sell the scrap rooftop condensing units to
whoever scraps them out will be enthusiastic to get $100 for a 25hp 3p motor
 
[486] said:
vfd or rpc
because it sounds like you mean rpc

call around to some mobile crane companies, ask who they sell the scrap rooftop condensing units to
whoever scraps them out will be enthusiastic to get $100 for a 25hp 3p motor
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Fuck, I should have thought of that.

Yet another example of how I lose my edge now that I'm making real white collar money. :shaking:

Yes, RPC, obviously. I always fuck up the acronym for some reason.
 
Scrap yard I frequent was charging around $5/hp for motors....that was last year and I'm sure they've gone up a bit like everyone else. Kicking myself because they always had a good assortment of 20-30hp on the ground. Last couple times I've been there they haven't had shit.
 
arse_sidewards said:
So I'm still casually looking for a motor in the 20-30hp range for a VFD. This came up. Seems kinda pricey but it is 30hp. Thoughts? Keep in mind I could make do with a motor that's a ton older and has a ton more hours on it than this one.


boston.craigslist.org

Worldwide Electric Corp 30 HP Electric Motor 3 phase - Industrial...

Worldwide Electric Corp 30 HP Electric Motor 3 phase - Industrial Explosion Proof The motor is in West Wareham MA MODEL XWWE 30-18-286T 230 V This motor was purchased from a electrical contractor...
boston.craigslist.org
Click to expand...
Thoughts?


Yeah, why so fucking big?

Unless you're going to have a gang of guys working in your home shop, thats 10x overkill for what you will most likely be doing.

Same with the 15hp motor on the flat belt lathe, its just not necessary for any reason I can see.
 
2020AT4 said:
Thoughts?


Yeah, why so fucking big?

Unless you're going to have a gang of guys working in your home shop, thats 10x overkill for what you will most likely be doing.

Same with the 15hp motor on the flat belt lathe, its just not necessary for any reason I can see.
Click to expand...
I don't want shit to let the smoke out or trip the RPC breaker when the 10hp compressor comes on while I'm running 10hp of something else. So if I want to put 20hp of power through the RPC motor I need 20-30hp of motor. It's not that rare that I have one friend or relative over working with me. I want to be able to tell them to face a part or something while I work on something else.
 
2020AT4 said:
Thoughts?


Yeah, why so fucking big?

Unless you're going to have a gang of guys working in your home shop, thats 10x overkill for what you will most likely be doing.

Same with the 15hp motor on the flat belt lathe, its just not necessary for any reason I can see.
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I've got a 10 at my dad's
it will not start even a baaby little 250A a motor-gen welder
 
My ten hp rotary goes into a big panic when I switch on the break press. Once it’s going the world is good again.
 
ThePanzerFuhrer said:
My ten hp rotary goes into a big panic when I switch on the break press. Once it’s going the world is good again.
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how many hp?
I'd imagine one of those could get by fine with minimal motor power, because all the force is coming from the flywheels anyways.

the welder I try to run has iirc about a 15hp motor, and maybe a hundred pounds of rotating mass that's fairly close to the axis of rotation
Pops the 60a breaker on the input side of the RPC before it reaches a couple hundred RPM.
I've gotten it to go once by wiring up a few smaller idler motors (well, firing up the mill, the shaper, and another smaller motor-gen welder) just to add rotating mass on the lines. Too much dicking around though.
 
[486] said:
how many hp?
I'd imagine one of those could get by fine with minimal motor power, because all the force is coming from the flywheels anyways.

the welder I try to run has iirc about a 15hp motor, and maybe a hundred pounds of rotating mass that's fairly close to the axis of rotation
Pops the 60a breaker on the input side of the RPC before it reaches a couple hundred RPM.
I've gotten it to go once by wiring up a few smaller idler motors (well, firing up the mill, the shaper, and another smaller motor-gen welder) just to add rotating mass on the lines. Too much dicking around though.
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His brake is a hydraulic type. A phase converter hates that type of loading. I like using vfd's for hydraulic machines.

My big brake is a flywheel type, takes about 45 seconds to bring the 1k lb flywheel up to speed. I don't use a converter but make it's own motor into a converter by adding capacitors on a start circuit. Great simple way to run something that uses stored energy and the motor stays running. All the other 3ph motors on the machine work from the main motors converter effect.
 
Dethmachinefab said:
My big brake is a flywheel type, takes about 45 seconds to bring the 1k lb flywheel up to speed. I don't use a converter but make it's own motor into a converter by adding capacitors on a start circuit. Great simple way to run something that uses stored energy and the motor stays running. All the other 3ph motors on the machine work from the main motors converter effect.
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here's how I got my converter wired so its all one button, I'm thinking its basically how you're doing it
phase converter.png

I've thought about wiring up some machines like that, but what had stopped me was thinking about the inrush on startup might be too much. Guess I'll be doing that in the future.
 
[486] said:
here's how I got my converter wired so its all one button, I'm thinking its basically how you're doing it
phase converter.png

I've thought about wiring up some machines like that, but what had stopped me was thinking about the inrush on startup might be too much. Guess I'll be doing that in the future.
Click to expand...
A RPC is basically just a static phase converter with a motor. If you have a machine with multiple motors like he does and one is gonna stay running the whole time then you can wire it so that the flywheel motor is the equivalent of the idler in the RPC.
 
arse_sidewards said:
A RPC is basically just a static phase converter with a motor. If you have a machine with multiple motors like he does and one is gonna stay running the whole time then you can wire it so that the flywheel motor is the equivalent of the idler in the RPC.
Click to expand...
Yep. I just put capacitors and a high amp momentary switch between a line and the 3rd load. I don't mind holding the momentary switch after hitting the start button until it ramps up for simplicity.
 
2020AT4 said:
Thoughts?


Yeah, why so fucking big?

Unless you're going to have a gang of guys working in your home shop, thats 10x overkill for what you will most likely be doing.

Same with the 15hp motor on the flat belt lathe, its just not necessary for any reason I can see.
Click to expand...



Expansion man...


You gotta think big:laughing:

Seriously though, I bought a 30 HP RPC. I don't regret it one bit, it sit's in the corner and does it's job.

The biggest reason I went that big is it will run everything I have at the same time If I chose, it would also run a 3 phase welder. Probably.

The neighbors know when it comes on:laughing:
 
arse_sidewards said:
So I'm still casually looking for a motor in the 20-30hp range for a VFD. This came up. Seems kinda pricey but it is 30hp. Thoughts? Keep in mind I could make do with a motor that's a ton older and has a ton more hours on it than this one.


boston.craigslist.org

Worldwide Electric Corp 30 HP Electric Motor 3 phase - Industrial...

Worldwide Electric Corp 30 HP Electric Motor 3 phase - Industrial Explosion Proof The motor is in West Wareham MA MODEL XWWE 30-18-286T 230 V This motor was purchased from a electrical contractor...
boston.craigslist.org
Click to expand...



As soon as you buy something a free one will pop up...Always does:laughing:
 
Dethmachinefab said:
Yep. I just put capacitors and a high amp momentary switch between a line and the 3rd load. I don't mind holding the momentary switch after hitting the start button until it ramps up for simplicity.
Click to expand...
start cap is enough to get it moving, huh
what kinda breaker are you running it on vs the motor's FLA?

I'd imagine inrush current has gotta be pretty huge what with it drawing the poop from 2 wires rather than 3, and with a terrible power factor to boot because the phase separation is wrong.
not that I'm doubting it works or anything, just interested in how much headroom you've got on the breaker that its on in order to make it work.
I could wire up my torpedo welder with a 100A breaker if I had to.
 
I've got it on a 60a breaker. Not sure what the motor says, it's probably around 20hp. Start up is like 45 sec, which isn't all that bad considering the amount of energy in the flywheel.
 
It's gotta make less than rated power, and probably run hotter too. I would wager it only works because of that flywheel.
 
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