Reference

Reference Tables

Print-ready reference tables for phase converter sizing, electrical requirements, and motor data. Use alongside our sizing guide and installation guide.

Table 1

Equipment Sizing Multiplier Table

Multiply your motor's nameplate HP by the multiplier for your load type. Round up to the next standard converter size.

Category	Multiplier	Equipment Examples	Why This Multiplier
Easy	× 1.0	Table saws, band saws, drill presses, grinders, belt sanders, fans, blowers, bench grinders	Low starting torque, predictable constant load, starts unloaded
Medium	× 1.5	Small engine lathes, mixers, pumps, conveyors, planers, jointers, small milling machines, woodworking shapers	Moderate starting current, variable load during operation
Hard	× 2.0	CNC machining centers, CNC lathes, engine lathes (large), press brakes, ironworkers, plasma tables, laser cutters	High inrush current, multi-motor loads, complex variable loading
Very Hard	× 2.5	Air compressors, HVAC units, dust collectors, grain dryers, irrigation pumps, refrigeration compressors, cold storage	Extremely high starting torque, capacitor-start motors, loads starting under full pressure/head

Multi-machine rule: Full multiplier for largest machine + 50% of multiplied HP for each additional simultaneous machine.
When in doubt: Go one size larger. Over-sized converters run cooler and last longer.

Table 2

Phase Converter Sizing Quick Reference

Common equipment HP values mapped to recommended converter HP by load type.

Motor HP	Easy Load (×1.0)	Medium Load (×1.5)	Hard Load (×2.0)	Very Hard (×2.5)
2 HP	3 HP	3 HP	5 HP	5 HP
3 HP	3 HP	5 HP	7.5 HP	10 HP
5 HP	5 HP	7.5 HP	10 HP	15 HP
7.5 HP	7.5 HP	10 HP	15 HP	20 HP
10 HP	10 HP	15 HP	20 HP	25 HP
15 HP	15 HP	25 HP	30 HP	40 HP
20 HP	20 HP	30 HP	40 HP	50 HP
25 HP	25 HP	40 HP	50 HP	60 HP
30 HP	30 HP	50 HP	60 HP	75 HP
40 HP	40 HP	60 HP	75 HP	100 HP
50 HP	50 HP	75 HP	100 HP	Call us

Table 3

Wire Size & Breaker Chart

Input wiring from main panel to converter at 230V single-phase. Based on NEC guidelines; verify with licensed electrician for your specific installation.

Converter HP	Input Current (est.)	Min. Wire Gauge (Cu)	Conduit Size (min.)	Breaker Size (2-pole)
3 HP	18A	#12 AWG	¾"	30A
5 HP	28A	#10 AWG	¾"	40A
7.5 HP	40A	#8 AWG	1"	60A
10 HP	50A	#6 AWG	1"	60A
15 HP	75A	#4 AWG	1¼"	100A
20 HP	100A	#2 AWG	1¼"	125A
25 HP	125A	#1 AWG	1½"	150A
30 HP	150A	#2/0 AWG	2"	200A
40 HP	200A	#3/0 AWG	2"	250A
50 HP	250A	#4/0 AWG	2½"	300A
60 HP	300A	350 kcmil	3"	350A
75 HP	375A	500 kcmil	3"	450A
100 HP	500A	600 kcmil (×2)	4"	600A

Values are estimates for single-conductor copper at 75°C in conduit. Adjust for aluminum (1 AWG size larger), run length over 100 feet (voltage drop calculation required), or ambient temperature over 86°F. Always verify with a licensed electrician.

Table 4

Motor FLA Reference

Approximate Full Load Amps for three-phase motors at 230V and 460V. Use for output wire sizing and overload protection. Check motor nameplate for exact values.

Motor HP	FLA at 230V (3Ø)	FLA at 460V (3Ø)	Typical Wire (230V)	Typical Disconnect (230V)
1 HP	3.6A	1.8A	#14 AWG	15A
1.5 HP	5.2A	2.6A	#14 AWG	15A
2 HP	6.8A	3.4A	#14 AWG	15A
3 HP	9.6A	4.8A	#12 AWG	20A
5 HP	15.2A	7.6A	#12 AWG	20A
7.5 HP	22A	11A	#10 AWG	30A
10 HP	28A	14A	#10 AWG	40A
15 HP	42A	21A	#8 AWG	60A
20 HP	54A	27A	#6 AWG	70A
25 HP	68A	34A	#4 AWG	90A
30 HP	80A	40A	#3 AWG	100A
40 HP	104A	52A	#2 AWG	125A
50 HP	130A	65A	#1 AWG	150A
60 HP	154A	77A	#2/0 AWG	200A
75 HP	192A	96A	#3/0 AWG	225A
100 HP	248A	124A	#350 kcmil	300A

FLA values from NEC Table 430.250. Output wiring should be sized at 125% of FLA per NEC 430.22. Always check actual motor nameplate FLA before final wire sizing.

Table 5

Voltage Balance Tolerance by Equipment Type

Maximum allowable voltage imbalance at three-phase equipment input terminals. Exceeding these values causes overheating, premature motor failure, and equipment faults.

Equipment Type	Max Imbalance	Recommended Converter	Notes
General shop motors (saws, pumps, grinders)	5%	NL Series	Standard rotary converters typically meet this
CNC machining centers (Haas, Mazak, etc.)	2%	PL Series	Check manufacturer installation manual for exact spec
Servo drives and amplifiers	2–3%	PL Series	Drives may fault on higher imbalance
Air compressors and HVAC	5%	NL Series or NLA	Less sensitive to imbalance than CNC; heat is main concern
Medical/laboratory equipment	1–2%	PL Series	Check equipment specification; often tightest requirement
Variable frequency drives (on converter output)	3%	PL Series	VFDs on converter output may interact; test before commissioning
Welding equipment (transformer-based)	5–10%	NL Series	Most tolerant of imbalance among three-phase loads

Voltage imbalance formula: % Imbalance = (Max deviation from average ÷ Average voltage) × 100. Measure all three line-to-line voltages (T1-T2, T2-T3, T1-T3) under actual load for accurate results.

Need custom calculations?

These tables cover the most common cases. For unusual installations, multiple machines, 460V equipment, or agricultural applications, call us for a custom analysis.

Call (800) 417-6568 Sizing Wizard