Frequently Asked Questions

Take the HP of your largest motor and multiply by 2. Then add the nameplate HP of any other motors that will run at the same time (no multiplier on those). Round up to the next Phoenix model size. Example: 10 HP mill + 2 HP lathe running simultaneously = (10×2) + 2 = 22 HP → GP25NL.

Full sizing guide with worked examples →

Yes — that's the most common setup. One Phoenix NL or PL converter can power your entire shop. Size it to handle all machines that might run simultaneously, applying the 2× rule only to the largest single motor.

Yes, and you need a different model. Compressors draw 6–8× nameplate amps at startup (high locked-rotor amps). Use the NLA Series (compressor duty) sized to 3× the compressor HP. A standard NL will fail to start compressors reliably. NLA Series details →

You need the NLT or NLTA Series, which include a built-in step-up transformer. They take 230V single-phase (standard service) and output 460V three-phase. If you already have 460V single-phase service, use the NH or PH Series instead.

Yes, within reason. Oversizing by one model size is fine and sometimes preferred — it reduces the converter's operating temperature and extends life. Extreme oversizing (3–4× what you need) can cause starting problems because the converter's idler motor may not receive enough current from the load to run efficiently. When in doubt, call us — we'll tell you the safe range.

NL is standard duty — mills, lathes, pumps, fans, general shop equipment. NLA is compressor duty — engineered for the high starting current that compressors, air handlers, and chillers require. Do not use an NL for compressor loads.

Near the panel, in a dry location with at least 12 inches of clearance on all sides for airflow. The converter runs warm under load — airflow is important. Avoid mounting directly above equipment that produces heat or moisture. NEMA 4 enclosures are rated for light moisture and dust but should not be submerged or hosed down.

Use the breaker sizing table on the Reference page. General rule: size the input wire and breaker to 250% of the converter's input full-load amps per NEC 455. The three-phase output wiring to each machine is sized normally to that machine's FLA.

No. Rotary phase converters do not use or produce a neutral on the three-phase output side. Your three-phase machines run on L1, L2, L3 only. The neutral from your panel feeds only single-phase loads in your shop — it does not connect to the converter.

Yes. The converter should be on its own two-pole breaker sized per NEC 455 (typically 250% of input FLA). Do not share this circuit with anything else.

With AutoLink (standard on all Phoenix converters), no — the converter starts automatically when any connected load calls for power and shuts down when all loads stop. You can also start it manually if preferred. Without AutoLink, you would need to start the converter first, but all current Phoenix units include AutoLink standard.

The converter itself is straightforward wiring. However, NEC 455 requires a licensed electrician for the service-panel connection in most jurisdictions, and most AHJs require a permit and inspection. We recommend using a licensed electrician for the panel connection and permitting, even if you run your own branch circuit wiring.

Almost certainly yes. Phoenix converters produce <2% voltage imbalance at rated load, which is within spec for virtually all modern CNC machines and VFD drives. If your machine manual specifies a maximum imbalance percentage, it's almost always 2–3%. The PL Series adds voltage monitoring as an extra layer of protection for sensitive equipment. Full CNC guide →

Yes. VFDs rectify incoming AC to DC internally, which makes them tolerant of moderate voltage imbalance. Phoenix's <2% output imbalance is well within range for all major VFD brands. Use the PL Series for additional voltage monitoring if the VFD manufacturer requires it.

Yes. We have customers running Haas VF series, Mazak Integrex, Fanuc-controlled machines, and Okuma on Phoenix converters. The key is correct sizing — call us with the machine's kVA rating from the nameplate and we'll verify the right model.

Yes, with proper sizing. Welders draw high current spikes for short durations. Sizing depends on the welder's input KVA and duty cycle. Call us with the welder's nameplate data and we'll confirm the right converter size.

Sometimes, with caveats. The generator must be able to supply 2–3× the converter's rated input current at startup. Generator voltage regulation under transient load is usually the limiting factor. Call us with your generator's specs and we can advise.

A moderate hum is normal — you're spinning an electric motor. Excessive noise, rattling, or a grinding sound is not normal. Check that the unit is mounted securely (vibration from loose mounting can amplify noise) and that nothing is obstructing the idler motor. If the noise is new and the unit was previously quiet, call us.

Check the three-phase output voltage leg-to-leg with a multimeter. All three legs should read within 5% of each other. If one leg is significantly low or missing, the converter may need service. Also verify the output breaker and all machine disconnects are closed. Call us at (602) 962-8859 — we troubleshoot over the phone at no charge.

Indefinitely with normal use. We have units in service from the 1980s. Phoenix converters have lifetime warranties — if a component fails, we support it. The TEFC cast-iron idler motor is the heart of the unit and is built for continuous industrial duty.

With AutoLink, the converter shuts down when all connected loads stop. Idle power consumption is essentially zero. Without AutoLink (older units), the idler motor spins continuously, consuming roughly 1–3% of rated HP in idle current. All current Phoenix units ship with AutoLink standard.

All Phoenix rotary phase converters carry a lifetime warranty on the converter components against defects in materials and workmanship. This covers the idler motor, control board, capacitors, and enclosure. It does not cover damage from improper installation, overloading, or physical damage. Call us — we stand behind every unit we sell.

Call (602) 962-8859 or submit a ticket. We troubleshoot over the phone first — most issues are resolved without shipping the unit. If the unit needs to come in, we'll provide a return shipping label.

Yes, always. Call (602) 962-8859 during business hours. We answer the phone and we know our equipment because we built it. There is no charge for technical support.