Electrical wiring question

[newbury]

rotary convertors are a piece of history from the bad old days when there was nothing better to make do with on the cheap. Now we go with a lower cost and more efficient variable frequency 3 phase drive supplied by single phase. Allows current limiting, torque limiting, start and stop ramping, reversing and variable rpm.

I've got the following 3 phase equipment:
5HP
5HP
3HP
3HP
2HP

None that will be run at the same time (I'm one person)

I've bought (~$100) a 10HP motor and planned on getting a 10 HP CNC-GRADE ROTARY PHASE CONVERTER for $200 so I can wire up my shop for 3 phase.

Are you saying there are VFD's so inexpensive I could dedicate one to each machine? If so where do I find them?

 

[LD1]

Rotary's are still about the cheapest and accaptable way to power a motor or multiple motors at full power from single phase.

Static are simpler and cheaper if buying new but usually limited to 2/3 of motor power. Usually not a problem for a home hobby guy running g a late and mill.

Advantage to rotary other than full power and cheap, you can set ONE up and power your whole shop.

VFD, can only power one motor, and alot of parameters to set up properly if you want to swap machines all the time.

But where vfds really shine is fingertip speed control and reverse at the push of a button. It's actually making the old step-pulley Bridgeport more desirable than the variable speed head due to cost and simplicity.

They both have their place. 5hp vfds can be had for $200-$300. If you were setting up one machine, it would make sense. If you have a whole shop of stuff you want powered, and speed control isn't needed, a 10hp or 20hp rotary makes sense.

Kinda like a HST cabbed tractor with 4wd and loader and all the bells and whistles is nice, but if all you need is a second machine for shuttling hay wagons....is it a wise use of money?

 

[buickanddeere]

I've got the following 3 phase equipment:
5HP
5HP
3HP
3HP
2HP

None that will be run at the same time (I'm one person)

I've bought (~$100) a 10HP motor and planned on getting a 10 HP CNC-GRADE ROTARY PHASE CONVERTER for $200 so I can wire up my shop for 3 phase.

Are you saying there are VFD's so inexpensive I could dedicate one to each machine? If so where do I find them?

Ebay is one of many sources. Either a VFD for each 3 phase machine . Or Setup one 3 phase inverter to supply a three phase service. Then wire each three phase machine to the service.

 

[CobyRupert]

Your inspector is an idiot.

:thumbsup:

... Right now it takes over $1000 of electricity to mine one. The bitcoin network as a whole consumes something like 45 million kilowatt hours a day. It is kind of like mining for gold - it takes money to get it.

If you try and mine on your own it would take forever to get a bitcoin. People join pools and they all work together and when one is found they split the profits.

The best miner on the market is the antminer S9. These cost about $3,500 each right now but at current prices will get you about $16 a day while consuming about $4 of electricity.

Does that include the HVAC? Most electricity consumed by computer loads is converted into heat that then requires A/C.

 

[roadhunter]

rotary convertors are a piece of history from the bad old days when there was nothing better to make do with on the cheap. Now we go with a lower cost and more efficient variable frequency 3 phase drive supplied by single phase. Allows current limiting, torque limiting, start and stop ramping, reversing and variable rpm.

I just love it when people paint with such a broad brush as if they know it all. There age advantages and disadvantages to each. You might do that but that doesn't mean that's best for every application. So what VFD would you recommend for a total load of 14.5 HP with a hard starting 10 HP hammermill as the biggest load without sacrificing any performance.

 

[roadhunter]

I've got the following 3 phase equipment:
5HP
5HP
3HP
3HP
2HP

None that will be run at the same time (I'm one person)

I've bought (~$100) a 10HP motor and planned on getting a 10 HP CNC-GRADE ROTARY PHASE CONVERTER for $200 so I can wire up my shop for 3 phase.

Are you saying there are VFD's so inexpensive I could dedicate one to each machine? If so where do I find them?

I'd focus on the advice LD1 posted. Each have thier place and limitations.

I'm waiting to see what VFD buckanddeer recommends for my applicaiton.
Automatic hammer mill system (AHS) - YouTube

This is what I ended up with.
AI-25
AI Industrial Converter American Rotary

 

[bdog]

:thumbsup:



Does that include the HVAC? Most electricity consumed by computer loads is converted into heat that then requires A/C.

They do not have to be located in an air-conditioned space if there is adequate airflow. Ours will be in an unused room in the house that has AC with the door closed. I fully expect it to get hot in there but it shouldn't impact the AC bill too much. I would put the things out in my shop but I am worried about all the welding and grinding dust getting sucked into the fans. On the bright side when winter comes they will offer heat.

 

[buickanddeere]

I'd focus on the advice LD1 posted. Each have thier place and limitations.

I'm waiting to see what VFD buckanddeer recommends for my applicaiton.
Automatic hammer mill system (AHS) - YouTube

This is what I ended up with.
AI-25
AI Industrial Converter American Rotary

Would not waste my time as you would still find fault with any one of a number of solutions presented if it was from myself.

 

[roadhunter]

Would not waste my time as you would still find fault with any one of a number of solutions presented if it was from myself.

Not true at all, I'm happy to listen to suggestions from you if you actually know what you are taking about. I think many of us are not familiar with VFD's and what they are best at running. You started this with your comments about how VFD's were superior to rotary converters so I asked which one you would recommend for my application.

So which one would you recommend?

 

[buickanddeere]

A VFD provides a true three phase power with exactly 120 degrees between phases . Applied voltage is also identical phase to phase . Three phase motors driven from a VFD vs a rotary converter can operate at full rated shaft HP without exceeding rated FLA on any phase . The VFD driven motor operates quieter and cooler. The motor starting torque , ramp up speed , stall torque, reversing and instant stop can be programmed . Rpms can be controlled .