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 .

 

[CobyRupert]

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.

Quick math: 12 amps/circuit x 6 circuits x 120V = 8640VA. Lets say 99% of this is heat, that's a heat load of over 8550 Watts (8.5 kilowatts) being dumped into the room, or 29,000 BTU/hr. That's substantial.

 

[buickanddeere]

What is the watts to compare them to the VAR's. the only heat from the reactive power is the I2R losses in the conductors, contacts, power supplies etc.

 

[CobyRupert]

What is the watts to compare them to the VAR's. the only heat from the reactive power is the I2R losses in the conductors, contacts, power supplies etc.

Most people agree, as do I, that pretty much all of the energy that goes into a computer is converted into heat.
How much of a computer's energy goes to heat? - Quora

 

[roadhunter]

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 .

In this case my machine has multiple motors all fed with a 40 amp 3 phase service. total of 3 - 1.5 HP motors and a 10 hp motor for the hammermill. There is a VFD on one of the 1.5 HP motors to adjust how fast the chips go into the hammer mill.

The other challenge is that there are chips in the hammer mill during startup which requires extra force to get spinning.

I spoke to several places about my application, a couple of which sold VFD's as well as rotary converters. None steered me toward a VFD. That's why I'm curious why you think a VFD is better for all applications including this.

 

[newbury]

Well "rule of thumb" says 2HP VFD for 1 HP of motor

Thus, the rule of thumb for sizing the single phase input on a three-phase drive is to use a VFD rated for 2 times the FLA of the motor. For example if your motor is a 10 HP motor with a FLA of 28 amps, then you would need to select a VFD with an amp rating of 56 amps which ends up being around 20 HP.Jan 18, 2014
VFD Buying Guide - VFDs.com
VFD Buying Guide

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.

So - prices from a quick look on ebay:
5HP needs 10HP vfd $255
5HP needs 10HP vfd $255
3HP needs 6HP vfd $223
3HP needs 6HP vfd $223
2HP needs 4HP vfd $133

So it will cost about $1100 for my solution.

I hadn't looked in a while so I thought maybe you had found a VERY inexpensive source for VFD drives.

It was my understanding that VFD's must be "tuned" for different motors.

 

[buickanddeere]

Well "rule of thumb" says 2HP VFD for 1 HP of motor



So - prices from a quick look on ebay:
5HP needs 10HP vfd $255
5HP needs 10HP vfd $255
3HP needs 6HP vfd $223
3HP needs 6HP vfd $223
2HP needs 4HP vfd $133

So it will cost about $1100 for my solution.

I hadn't looked in a while so I thought maybe you had found a VERY inexpensive source for VFD drives.

It was my understanding that VFD's must be "tuned" for different motors.

one 10HP VFD will run any load one at a time. Each electrical load will have to depend on it's own thermal protection from overloads. Frequency/rpm control, reversing and ramped starting would remain possible with one VFD supplying any of the motor loads.

 

[bdog]

I don't mind at all carry on but it cracks me up. My thread was about how to wire up a breaker box and it has devolved into half the people talking about bitcoin mining and half the people talking about VFDs. I got the panel wired up and running so life is good.

 

[joefromga]

Bitcoin went up nearly 300$ yesterday.

 

[TMGT]

I don't mind at all carry on but it cracks me up. My thread was about how to wire up a breaker box and it has devolved into half the people talking about bitcoin mining and half the people talking about VFDs. I got the panel wired up and running so life is good.

Glad to hear, I was getting worried I missed some question about running 3phase equipment.........

As for computer heat, I use to heat a small unisulated block dorm room with 2 older laptops, this was in Michagan.

 

[Streetcar]

I don't mind at all carry on but it cracks me up. My thread was about how to wire up a breaker box and it has devolved into half the people talking about bitcoin mining and half the people talking about VFDs. I got the panel wired up and running so life is good.

Bdog
Back to bitcoin. What is the reason (economic value) in bitcoin mining? What does bitcoin originator gain by solving the algorithm