Welcome to Elimia Industrial
Providing Economical Power Solutions for All
Please use this web page and links to answer common questions we get asked.  As always, we are here to answer questions directly via phone or email.  We will help all customer's large and small to get the information they need. 

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What size Rotary Converter do I need?

Generally speaking it is always advantageous to oversize the phase converter.  Oversizing means that your equipment and phase converter will run with less stress, preform better and run cooler.  Under sizing the phase converter forces the generated phase voltage to drop.  The reduced voltage can affect the life of your equipment.

We have comprised a list of equipment with a numerical multiplier.  Use this number multiplied by your machine HP or wattage to size your converter.  *Please note, every installation and load is unique.  Many factors affect the capability of the rotary converter.  Please call Elimia to discuss your individual situation.  We want to help anyway we can and we will not try to sell you something you don't need...


You have a 3 phase, 10 HP air compressor.  Using the multiplier of 2.0 you will need at least a 20 HP rotary converter.

Air compressor---------------------------2.0                Air compressor 10HP+ ---------------2.0 - 2.5
Blower -----------------------------------1.75                Battery Charger ------------------------1.75
Dishwasher ------------------------------1.5                Drill ---------------------------------------1.5
Dryer -------------------------------------1.5                Dust Collector --------------------------1.75
EDM Machine ----------------------------2.0                Glue Machine ----------------------------1.5
Grinder -----------------------------------1.5                Hoist --------------------------------------1.5
Heater ------------------------------------1.5                HVAC -------------------------------------1.75
HVAC Total 5HP+ ------------------------2.0                Iron Worker Hydraulic ------------------1.75
Iron Worker Cam Type -----------------2.0                Injection Molding ------------------------1.75
Lathe --------------------------------------1.5                Lathe 5HP+ -------------------------------2.0
Lathe Newman Motor -------------------2.5                Lathe Turret -----------------------------2.5
Meat Grinder -----------------------------1.5                Milling Machine ---------------------------1.5
Metal Brake -------------------------------1.5                Metal Roll ---------------------------------1.5
Metal Shear -------------------------------1.5                Metal Shear Cam Type ------------------1.75
Mixer --------------------------------------1.5                Pump --------------------------------------1.75
Planer -------------------------------------1.75                Plasma Cutter ----------------------------1.75
Press ---------------------------------------1.5                Tire Balancer -----------------------------1.5
Sander -------------------------------------1.5                Saw Chop ---------------------------------1.5
Saw Table ---------------------------------1.5                Saw Band ----------------------------------1.5
Saw Radial Arm --------------------------1.75                Shaper -------------------------------------1.75
Vacuum ------------------------------------2.0                Washer ------------------------------------1.5
Welder ------------------------------------1.75        
Do I need a CNC rated converter?

Some machines use digital electronics or computer controlled devices and systems.  For these equipment types a special phase converter is needed, the CNC Grade.  Many machines with electronic systems also incorporate phase/voltage monitoring devices.  These devices provide protection for the electronics by watching the voltage for each phase and "shutting down" in the event the voltage balance is outside parameters.

All Elimia Phase Converters are capable of running equipment with a 5% voltage tolerance.  It should be noted that on some Elimia models sizing is critical for proper CNC operation.  Meaning, a CNC grade phase converter cannot run electronics if it is under sized for the machine.

If your equipment has electronic controls or controller and requires a voltage balance guarantee then you need a CNC grade phase converter.

In order to meet CNC balance requirements a phase converter must be balanced under no load and remain balance at all times while your machine is running.  While your machine is running and working the load demand is constantly changing.  These load changes create various voltage balance conditions.  The phase converter must be sized large enough to hold the generated phase voltage within the machine's specifications. 

Example:  You have a milling machine center with a 15 HP spindle motor with a total power requirement of 20 KW.

-Your machine's controls require 5% balance reference phase to phase.
-Voltage required is 230VAC 3ph +/- 7%.
-Machine requires 50 Amps @ 230 VAC

In order to properly run this machine a CNC grade 30 HP converter will be needed.

Do I need a transformer?

If your machine requires any voltage other than 230 VAC 60 Hz you will probably need a transformer.

With a transformer and a rotary phase converter you can run equipment of most all voltages. 

If your equipment requires a voltage of 200 - 220 VAC you may or may not need a transformer.

Most of the time your single phase power source will be nominal 230 VAC.  If a measurement is done it is likely that the actual voltage will be 240 VAC and 245 VAC+ is not uncommon.  When a phase converter produces the third phase it is desirable for the generated phase to be ~10 Volts higher reference to phase one and two. 

Generally, when the three phase voltage is measured (phase to phase) at the converter under no load, you will read approximately the following:  L1 to L2 = 240 VAC; L1 - L3 = 245 VAC; L2 - L3 = 250 VAC.  Therefore, a phase converter powered by 240 VAC single phase should not be used to directly power this machine.  A 3 phase distribution transformer would be needed to change the voltage from 240 to 208.  We recommend using transformers on the output of the phase converter when possible.

You would also need a transformer when running any equipment other than 230 VAC +/- 10%.  It is very common to run machines from a phase converter/transformer that are rated 380 Volt up to 600 Volts.  We can help you get set up with the right phase converter/transformer system for the task.

Can I run multiple machines from my rotary phase converter?

Yes.  We look at rotary phase converters as a power source, just like your single phase power service.  Once the third phase is generated by the converter a 3 phase load center can be installed and 3 phase power can be properly distributed out to each machine.

The number of machines and the capacity is limited by the size of your phase converter or distribution service.  As you load the phase converter with various machines the voltage of the generated phase drops.  This voltage should be observed and should be limited to not more than 15 - 20 Volts below L1 - L2 measurement.  Forcing a machine to run with a third phase voltage more than 20 Volts low can shorten the life of your equipment.  For sensitive equipment the third phase voltage should be not more than 10 Volts low.

Remember, the voltage measurement of L1 to L2 is the same as the power feeding your phase converter as two phases just pass through the converter.  The third phase is a product of phase L1 and L2.

Do rotary converters cost a lot to run?

No.  Rotary phase converters are usually much cheaper to operate versus diesel or gas generators or pumps.  One cost comparison we have done showed a cost about 5/8 less than diesel.  Customer was using a diesel engine to direct drive a large water pump.  The cost of operation for the diesel system was ~$6.25 per hour.  We set him up with a 40 HP rotary converter to drive a 20 HP electric motor pump.  The GPM of each system was very close however the operation cost of the electric system was $2.33 per hour.

Another customer was paying ~$650.00 per month for a 480 VAC 3 phase service whether it was used or not used.  He had this service to run a 480 VAC knife grinder for a chipper mill.  We worked with the customer and instructed him how to set up the machine to run at 230 VAC 3 phase and supplied him with a 15 HP rotary converter.  He was able to disconnect his 480 Volt service and use his office power of 230 VAC single phase to power the converter. 

Cost to connect to three phase power versus rotary phase converters?

A very common situation we hear about is an existing business has decided to relocate to another location where 3 phase is not available or where a 3 phase service is cost prohibited.  Customer's tell us that thier power company is asking $10,000 - $300,000 cost to run 3 phase to thier location.  Elimia can help set up a whole shop system at a much lower cost than running 3 phase and will operate very close in power cosumption. 

Operating cost versus electric company supplied 3 phase?

In many cases the way that single phase power is metered by the power company is different than their 3 phase metering.  For 3 phase services power companies consider both total kW per hour and kW peak.  They rate the kW peak as a "demand charge".  The demand charge may add 40% or more to a 3 phase service rate cost.  Although this varies from electric company to company, in nearly all cases the extra cost for the demand charge is more than the cost of the rotary phase converter electric consumption.  Therefore, in many cases the energy cost is less to run a rotary converter than grid 3 phase power.

Other electric companies use a policy of threshold kWh usage to trigger demand charges.  This applies to single phase and three phase customers, residential and commercial.  Some use a threshold of 2,000 or 2,500 kWh.  If or when your consumption exceeds the threshold a demand charge occurs.  In these cases the energy used to run the phase converter should be considered.

Commonly, a demand charge is based around the highest kW usage for a 15 minute period.  For very large companies with high steady electrical consumption the demand charge effect is positive.  For most small businesses running three or so machines the impact is negative.

Will my existing electrical service support a rotary converter?

There are many factors that can effect the operation of your rotary phase converter and/or 3 phase equipment.  One of the most critical factors is your existing electrical service size.  Small rotary converters, 10 HP or smaller, can be be run by most resisdential electrical services.  We recommend a service size of 100 Amps minimum.  But, obviously the total load on each electrical service is the determining factor.  For rotary converters 15 HP and larger we recommend a shared electrical service of 200 Amps or larger. 

A lot of customer's don't consider thier electrical service but it is crucial to discuss and review your shop's electrical service when running large equipment.  It is very common for the power company to be supplying pole power via a small 15 KVA transformer.  A transformer of this size may actually not be capable of properly running a 15 HP rotary converter and equipment.  As said, every situation is different and requires review by Elimia or other professionals.  In general, if your shop is sharing power with your home a review of your electrical service should be done.

In most cases electrical companies want to sell you more power.  And if you need a larger grid transformer or larger incoming wiring they usually provide without hesitation.  We talk to power company engineers, technicians and linemen regularly.  We have found all of them easy to work with and quick to provide what you need to get your equipment to operate correctly. 

What size wire & serivce is needed for an Elimia rotary converter?

Wire size depends primarly on three variables:  Load size; Distance and Conductor type.
Use the chart below to determine if your existing electrical service can support a rotary converter.

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June 2013, Elimia is proud to add several products to our line. Including: Baldor/ABB VFD and packaged drives; Federal Pacific Transformers; Schaefer Enclosures; Enclosure Solutions Enclosures.