Owners share advice on ways to upgrade the shop's power supply. June 12, 2005
Question
I have recently acquired a planer, jointer, and band saw that all have a 3 phase motor. I am planning on building a shop on my land, and am left with 3 options and would be interested in others opinions. The options are to:
1. Try to get the power company to pull 3 phase lines to my shop (3 phase runs in front of my house).
2. Change out the motors to single phase.
3. Use a phase converter.
Which is the easiest and cheapest?
Forum Responses
(Cabinetmaking Forum)
From contributor R:
I went through this a few years back when I bought my first Bander. I never considered changing out the motors as an option. The power company wanted $8,000 to get a 3 phase to my shop and I was still going to have to pay an electrician to get the 3 phase into the shop, so I was looking at well beyond $10K.
It was a simple decision to go with a 15 horse-power rotary converter which cost $1,500. The electrician charged me $500 to install it with one outlet. If you go with the converter, go with the biggest you can afford. I should have looked into a 20 horse power converter.
I've been using all methods of phase conversion for 25 years, and in a nutshell, the answer for your application is clearly a rotary converter. A static will run about $200 and you can buy a used three phase motor for cheap, if you look around.I would not make this decision until after you talk to the power company. I faced the same situation with a three phase in front of my house. After I provided a list of equipment that I would be running, they ran the three phase power overhead for no charge. I had 400 amp service brought in and it cost about $6000 for wiring up my shop. This included a 400 amp three phase panel with breakers. A 200 amp panel was about a third of the price.
I have also used rotary converters and they do work ok, but they aren’t as nice as the real thing. If you buy any new equipment like a edgebander, widebelt sander, CNC, etc., phase converters can cause you problems with warranties. All this type of equipment requires all legs of the power to be balanced. I'm not saying you can't do it, but it often requires buck boosters to go with your converter.
I built my shop last year, and didn't even waste a call to the power company - they'd want more than the price of the converter just to engineer and estimate the extra lines. A 20 horse-power Gentec was simple to install, inexpensive, lives in the basement, runs everything, and is trouble free and quiet.As one who may move his shop from a 3ph to 1ph, does each piece of equipment have to have its own converter? Can you run multiple pieces of equipment at the same time?To contributor B: One big phase converter, powered from your single-phase source, provides current to a three-phase panel which then provides separate circuits to the machines you want to run on it.You should talk to the power company first. If there is 3 phase power going past your shop, the power company may only charge you for a transformer. Or as someone has already said, they may charge you nothing if they think the revenue warrants it.
I have used a rotary converter for 6 years with no problems, but if I add the new wide belt I am going to have to make major additions. All in all, if you can get a 3-phase from the power company, you will be better off over the long haul.
Comment from contributor O:
When I showed the power company how much load would be dumped on their line for new single phase equipment, they decided it would be better for them if we bought three phase and they ran the lines to the shop at their expense.
You just bought an exciting new machine for your home or commercial shop only to find that it takes 3 phase power and you only have access to single-phase power from your power lines. What options do you have to get your machine up and running as quickly and cost-effectively as possible?
The most important question we ask to figure this out is: what kind of equipment are you powering?
Do you have a single motor that needs to be speed controlled or to run on 3 phase power? Would you like to reduce the amps your motor draws when it starts up? Then a Variable Frequency Drive (VFD) can be a great cost-effective solution to power your single motor.
VFDs connect directly to a motor and are not designed to power a whole machine or multiple motors. A VFD is primarily used to control the speed of a motor. This is great when you need to adjust the speed of your operation (eg. speed up a drill press or slow down a conveyor belt), or when you want to start or stop slowly.
The electrical output of a VFD creates a pulse rather than a constant electrical supply which is called Pulse Width Modulation. A VFD will output pulses so that the average of those pulses over time produces a sine wave. Variable Frequency drives ramp up the speed of the motor over time, which is called soft-starting. People buy VFDs for variable speed control of motors or to reduce the amps a motor draws when it starts up. This can make for the smooth operating of your motor and extend the motor’s life span.
If you have a single motor that you are trying to power then a Variable Frequency Drive is a great cost-effective solution.
If you have a machine with one or more motors that need 3 phase power then a Rotary Phase Converter is a great choice.
A Rotary Phase Converter is a power supply that converts single phase power to 3 phase power. They can power a machine with a single motor or multiple motors.
Rotary Converters are made up of a panel and an electrical generator. When the converter is on, the generator is spinning. The generator is basically a specially designed electric motor with no driveshaft. The generator needs to spin continuously even when there is no load on the converter. The larger the rotary phase converter, the more power it will consume to produce three-phase electricity from a single-phase source.
Rotary Phase Converters are a cost effective option and can work well for people with 1 or 2 machines, often in a home shop or commercial workshop.
If you have a machine that requires high-quality power, such as a CNC machine or a machine that is computer controlled then a Digital Phase Converter is the best option for you.
Digital Phase Converters produce high-quality power which is balanced across 3 lines. A digital phase converter is a power supply. Digital Phase Converters have the versatility to be able to connect directly to your machine or through a breaker panel to power multiple machines.
On a rotary converter, when the machine is loaded down the rotary converter’s voltage fluctuates. This would be problematic with a CNC machine. When you have a precision machine the voltage imbalance and fluctuation that can occur in a rotary phase converter can cause the motor on a CNC machine to not perform ideally. With a Digital Phase Converter, you get perfectly balanced power that can run your CNC seamlessly.
Whether you have a computer-controlled machine in your shop or farming equipment out in the field, Digital Phase Converters come in multiple different sizes and voltages to fit your phase conversion needs.
If your machine uses computer controls then a digital phase converter will give you the best possible power. If your machine doesn’t use computer controls (for example, a table saw or edge bander) a rotary phase converter is a good cost-effective option. If you are looking to control the speed, or power a single motor then a VFD may be right for your job.
Let the experienced journeymen at Electram help you find the right phase converter for your equipment. Give us a call or fill out our quick and easy phase converter checklist to get your machine up and running in no time!
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