Size a buck-boost transformer on load amps, not load kVA. Multiply the load amps by the secondary volts you connect in series, and pick the next VA size up. A 20 A load boosted with a 32 V secondary needs 640 VA, so a 750 VA unit. The cross reference below matches Micron buck-boost units to Acme, Square D, Eaton, GE, HPS, Jefferson, Hevi-Duty and FPC part numbers.
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The three Micron buck-boost groups
| Group | Primary | Secondary | Sizes |
|---|---|---|---|
| A | 120 x 240 V | 16/32 V | 50 VA to 7.5 kVA |
| B | 240 x 480 V | 24/48 V | 50 VA to 7.5 kVA |
| C | 120 x 240 V | 12/24 V | 50 VA to 7.5 kVA |
Source: Micron buck-boost price schedule MTC-12A and Micron buck-boost product page. Single phase, 600 V class, two primary and two secondary windings. Wired as an autotransformer for buck or boost. Wired as an isolation transformer they give 12, 16, 24, 32 or 48 VAC.
How to size it
| Step | What to do |
|---|---|
| 1 | Find the line voltage you have and the voltage the load needs. |
| 2 | Pick the group and connection that gets you closest. Example: Group A, primary in series on a 208 V line, secondaries in series, boosts to about 236 V. |
| 3 | Find the load amps from the nameplate. |
| 4 | Transformer VA = load amps x rated secondary volts in that connection (32 V for Group A secondaries in series). |
| 5 | Pick the next standard VA size up. For three phase, Micron banks two units (open delta) or three units. |
Worked example: 230 V motor on a 208 V line
| Item | Numbers | Result |
|---|---|---|
| Connection | Group A, 240 V primary on 208 V, 32 V secondary in series | 208 x 272 / 240 = about 236 V out |
| Load | Single phase motor, 20 A | |
| VA needed | 20 A x 32 V | 640 VA |
| Pick | Next size up, Group A | 750 VA, Micron JH750A1EB1A15 (was J750A1EB1A02). Replaces Acme T181059 or Square D 750SV46F |
Example values only. Check the motor nameplate voltage range and the line voltage under load before you order. We check the connection with you.
Where Micron says not to use one
Micron says buck-boost units are mainly for motor loads. Do not use one for a motor control circuit, to fix a line that swings up and down, or to get a neutral on a delta system. Use a control transformer or a regular two-winding transformer for those. On a 208Y/120 grounded system, a boost to 240 V leaves 139 V to ground. If you need 240/120 V with a center ground, use a two-winding transformer.
Buck-boost cross reference
Group A: 120 x 240 V primary, 16/32 V secondary
| VA | Micron (current) | Micron (old) | Acme | Eaton C-H | Hevi-Duty | FPC | GE | HPS | Jefferson | Square D |
|---|---|---|---|---|---|---|---|---|---|---|
| 50 VA | JH050A1EB1A14 | J050A1EB1A01 | T181054 | S10N06A81N | Ask | K1XGF16-0.05 | 9T51B0122 | QC05ESCB | 416-1200-000 | 50SV46A |
| 100 VA | JH100A1EB1A14 | J100A1EB1A01 | T181055 | S10N06A82N | Ask | K1XGF16-0.1 | 9T51B0124 | QC10ESCB | 416-1201-000 | 100SV46A |
| 150 VA | JH150A1EB1A14 | J150A1EB1A01 | T181056 | S10N06A83N | HS20B150 | K1XGF16-0.15 | 9T51B0125 | QC15ESCB | 416-1211-000 | 150SV46A |
| 250 VA | JH250A1EB1A14 | J250A1EB1A02 | T181057 | S10N06P26P | HS20B250 | K1XGF16-0.25 | 9T51B0127 | QC25ESCB | 416-1221-000 | 250SV46B |
| 500 VA | JH500A1EB1A14 | J500A1EB1A02 | T181058 | S10N06P51P | HS20F500B | K1XGF16-0.5 | 9T51B0128 | QC50ESCB | 416-1231-000 | 500SV46B |
| 750 VA | JH750A1EB1A15 | J750A1EB1A02 | T181059 | S10N06P76P | HS20F750B | K1XGF16-0.75 | 9T51B0129 | QC75ESCB | 416-1241-000 | 750SV46F |
| 1 kVA | JH001K1EB1A15 | J001K1EB1A02 | T113073 | S10N06P01P | HS20F1B | K1XGF16-1 | 9T51B0130 | Q1C0ESCB | 416-1251-000 | 1S46F |
| 1.5 kVA | JH1X5K1EB1A15 | J1X5K1EB1A02 | T113074 | S10N06P16P | HS20F1.5A | K1XGF16-1.5 | 9T51B0131 | Q1C5ESCF | 416-1261-000 | 1.5S46F |
| 2 kVA | JH002K1EB1A14 | J002K1EB1A02 | T113075 | S10N06P02P | HS20F2A | K1XGF16-2 | 9T51B0132 | Q002ESCF | 416-1271-000 | 2S46F |
| 3 kVA | JH003K1EB1A15 | J003K1EB1A03 | T113076 | S10N06A03N | HS20F3A | K1XGF16-3 | 9T51B0133 | Q003ESCF | 416-1281-000 | 3S46F |
| 5 kVA | JH005K1EB1A15 | J005K1EB1A03 | T113077 | S10N06A05N | HS20F5A | K1XLF16-5 | 9T21B1040G02 | Q005ESCF | 416-1291-000 | Ask |
| 7.5 kVA | J7X5K1EB1A03 | Same | T213078 | S10N06A07N | HS20F7.5A | Ask | Ask | Ask | 416-2201-000 | Ask |
Group B: 240 x 480 V primary, 24/48 V secondary
| VA | Micron (current) | Micron (old) | Acme | Eaton C-H | Hevi-Duty | FPC | GE | HPS | Jefferson | Square D |
|---|---|---|---|---|---|---|---|---|---|---|
| 50 VA | JH050A1KC1A14 | J050A1KC1A01 | T181061 | S20N08A81N | Ask | K2XGF24-0.05 | 9T51B0202 | QC05DTCB | 416-1400-000 | 50SV82A |
| 100 VA | JH100A1KC1A14 | J100A1KC1A01 | T181062 | S20N08A82N | Ask | K2XGF24-0.1 | 9T51B0204 | QC10DTCB | 416-1401-000 | 100SV82A |
| 150 VA | JH150A1KC1A14 | J150A1KC1A01 | T181063 | S20N08A83N | HS22B150 | K2XGF24-0.15 | 9T51B0205 | QC15DTCB | 416-1411-000 | 150SV82A |
| 250 VA | JH250A1KC1A14 | J250A1KC1A02 | T181064 | S20N08P26P | HS22B250 | K2XGF24-0.25 | 9T51B0207 | QC25DTCB | 416-1421-000 | 250SV82B |
| 500 VA | JH500A1KC1A14 | J500A1KC1A02 | T181065 | S20N08P51P | HS22F500B | K2XGF24-0.5 | 9T51B0208 | QC50DTCB | 416-1431-000 | 500SV82B |
| 750 VA | JH750A1KC1A15 | J750A1KC1A02 | T181066 | S20N08P76P | HS22F750B | K2XGF24-0.75 | 9T51B0209 | QC75DTCB | 416-1441-000 | 750SV82F |
| 1 kVA | JH001K1KC1A15 | J001K1KC1A02 | T137920 | S20N08P01P | HS22F1B | K2XGF24-1 | 9T51B0210 | Q1C0DTCB | 416-1451-000 | 1S82F |
| 1.5 kVA | JH1X5K1KC1A15 | J1X5K1KC1A02 | T137921 | S20N08P16P | HS22F1.5A | K2XGF24-1.5 | 9T51B0211 | Q1C5DTCF | 416-1461-000 | 1.5S82F |
| 2 kVA | JH002K1KC1A15 | J002K1KC1A02 | T137922 | S20N08P02P | HS22F2A | K2XGF24-2 | 9T51B0212 | Q002DTCF | 416-1471-000 | 2S82F |
| 3 kVA | JH003K1KC1A15 | J003K1KC1A03 | T137923 | S20N08A03N | HS22F3A | K2XGF24-3 | 9T51B0213 | Q003DTCF | 416-1481-000 | 3S82F |
| 5 kVA | JH005K1KC1A15 | J005K1KC1A03 | T137924 | S20N08A05N | HS22F5A | K2XLF24-5 | Ask | Q005DTCF | 416-1491-000 | Ask |
| 7.5 kVA | J7X5K1KC1A03 | Same | T243570 | S20N08A07N | HS22F7.5A | Ask | Ask | Ask | 416-2401-000 | Ask |
Group C: 120 x 240 V primary, 12/24 V secondary
| VA | Micron (current) | Micron (old) | Acme | Eaton C-H | Hevi-Duty | FPC | GE | HPS | Jefferson | Square D |
|---|---|---|---|---|---|---|---|---|---|---|
| 50 VA | JH050A1EA1A14 | J050A1EA1A01 | T181047 | S10N04A81N | HS19B50 | K1XGF12-0.05 | 9T51B0102 | QC05ERCB | 416-1100-000 | 50SV43A |
| 100 VA | JH100A1EA1A14 | J100A1EA1A01 | T181048 | S10N04A82N | HS19B100 | K1XGF12-0.1 | 9T51B0104 | QC10ERCB | 416-1101-000 | 100SV43A |
| 150 VA | JH150A1EA1A14 | J150A1EA1A01 | T181049 | S10N04A83N | HS19B150 | K1XGF12-0.15 | 9T51B0105 | QC15ERCB | 416-1111-000 | 150SV43A |
| 250 VA | JH250A1EA1A14 | J250A1EA1A02 | T181050 | S10N04P26P | HS19B250 | K1XGF12-0.25 | 9T51B0107 | QC25ERCB | 416-1121-000 | 250SV43B |
| 500 VA | JH500A1EA1A14 | J500A1EA1A02 | T181051 | S10N04P51P | HS19F500B | K1XGF12-0.5 | 9T51B0108 | QC50ERCB | 416-1131-000 | 500SV43B |
| 750 VA | JH750A1EA1A15 | J750A1EA1A02 | T181052 | S10N04P76P | HS19F750B | K1XGF12-0.75 | 9T51B0109 | QC75ERCB | 416-1141-000 | 750SV43F |
| 1 kVA | JH001K1EA1A15 | J001K1EA1A02 | T111683 | S10N04P01P | HS19F1B | K1XGF12-1 | 9T51B0110 | Q1C0ERCB | 416-1151-000 | 1S43F |
| 1.5 kVA | JH1X5K1EA1A15 | J1X5K1EA1A02 | T111684 | S10N04P16P | HS19F1.5A | K1XGF12-1.5 | 9T51B0111 | Q1C5ERCF | 416-1161-000 | 1.5S43F |
| 2 kVA | JH002K1EA1A15 | J002K1EA1A02 | T111685 | S10N04P02P | HS19F2A | K1XGF12-2 | 9T51B0112 | Q002ERCF | 416-1171-000 | 2S43F |
| 3 kVA | JH003K1EA1A15 | J003K1EA1A03 | T111686 | S10N04A03N | HS19F3A | K1XGF12-3 | 9T51B0113 | Q003ERCF | 416-1181-000 | 3S43F |
| 5 kVA | JH005K1EA1A15 | J005K1EA1A03 | T111687 | S10N04A05N | HS19F5A | K1XLF12-5 | 9T21B1037G02 | Q005ERCF | 416-1191-000 | Ask |
| 7.5 kVA | J7X5K1EA1A03 | Same | T211688 | S10N04A07N | HS19F7.5A | Ask | Ask | Ask | 416-2101-000 | Ask |
Source: Micron Industries transformer cross reference MINT16A (January 2016), buck-boost section. Group B primary per Micron price schedule MTC-12A. Current Micron JH numbers from FactoryMation Micron buck-boost listings (October 2026), where each old J number is marked discontinued with the JH number as its replacement. The 7.5 kVA units keep their J number. We confirm the Micron number on every quote. HPS is Hammond Power Solutions, a separate company from Hammond Manufacturing. Micron does not guarantee the competitor data is error free; check ratings before you swap.
Common questions
How do I size a buck-boost transformer?
Multiply the load amps by the rated secondary volts in the connection you use. Pick the next VA size up. A 20 A load on a 32 V boost needs 640 VA, so a 750 VA unit.
Why is a 750 VA buck-boost enough for a 4.7 kVA load?
In buck or boost, the transformer only carries the extra volts, not the whole load. At 236 V and 20 A the load is about 4.7 kVA, but the transformer only handles 32 V x 20 A.
What replaces an Acme T181055?
Micron JH100A1EB1A14, Group A, 100 VA (old number J100A1EB1A01). Same 120 x 240 V primary and 16/32 V secondary.
Can I use a buck-boost on three phase?
Yes. Micron banks two units in open delta or three units. The load amps and the system wiring set how many you need. Send the line voltage, load voltage and amps.
Can a buck-boost give me a neutral?
No. Micron says not to use one to get a neutral on a delta system. Use a two-winding transformer.
Get it crossed and quoted
Send the old part number, or the line voltage, the load voltage and the load amps. We send back the Micron buck-boost part and how to wire it.
Request a QuoteBook 30 Minutes to Review the ApplicationCall 248-830-4850
Related: Micron control transformers by kVA · Control transformer VA sizing · Micron · Transformers · All cross references
Acme, Eaton, Cutler-Hammer, Hevi-Duty, Emerson, FPC, GE, HPS, Hammond Power Solutions, Jefferson, Square D and Schneider Electric are trademarks of their owners. Applied Control Inc. is not affiliated with them. Names appear only to identify the part being replaced. Check the current manufacturer datasheet before you specify.