Eaton Bussmann FWP-25A22FA Fuse

(Standard part number: FWP-25A22F. The suffix FA is a trade designation; AMP25 means 25A and is not part of the original Eaton model number.)

Product Type: aR IEC cylindrical high-speed semiconductor fuse (ceramic tube, ferrule terminals), 22×58mm size

Model Code Explanation

FWP: Bussmann IEC high-speed semiconductor fuse series

25: Rated current 25A

A: aR (semiconductor protection, short-circuit protection only; not suitable for sustained overload)

22: Size code for 22×58mm

F: No striker / no fuse indication (FI = with striker, can actuate microswitch)

FA: Market / customs alias; official part number is FWP-25A22F

AMP25: Simple current marking of 25A, not part of original model

Core Electrical Specifications

Rated Voltage: 700V AC / 700V DC (IEC/UL)

Rated Current: 25A

Breaking Capacity: AC 200kA (symmetrical rms); DC 50kA @700Vdc

Fuse Class: aR (semiconductor short-circuit protection)

Pre-arcing I²t: 37; Total clearing I²t @700VAC: 530

Rated Power Dissipation: 6W

Form Factor: 22×58mm, ceramic tube, copper ferrules at both ends

Net Weight: Approx. 62.6g

Certifications & Compliance

UL Recognized JFHR2, CSA, CE, RoHS

Compatible Fuse Holder: JM70100 (matching safety fuse base)

Typical Applications

Short-circuit protection for DC busbars, DC drives, frequency converters, rectifiers / power converters, SCR and IGBT semiconductor devices. Widely used in PV energy storage, servo power supplies and UPS DC sides.

Note: aR provides short-circuit protection only and cannot replace gR overload protection.

Comparison with Similar Models

FWP-25A22F: No striker (this model)

FWP-25A22FI: With striker, triggers microswitch for alarm upon melting

FWP-25G22F: gR class (overload + short-circuit protection), 600V version

FWP-25A22F / FWP-25A22FI (22×58mm FWP aR Cylindrical High-Speed Fuse)

Applicable models: FWP-25A22F (no striker) / FWP-25A22FI (with striker)

Basic Electrical Table

Important Reminder: The FI model is derated to 500V DC. Do not use FI for DC bus >500V; use F version only. For AC operation, both versions have identical characteristics, I²t and time-current curves.

Time-Current (T-C) Characteristic Notes (Datasheet 720026)

Curves shown are nominal melt curves for aR fuses:

1. Almost no operation under low-magnitude overload: aR is designed exclusively for semiconductor short-circuit protection, not conventional overload protection. Melting time is extremely long at 1.6×In (40A), so it cannot be relied on for overload protection.
2. Short-circuit region (approx. 10×In): Fast current-limiting melting with low I²t to protect IGBT/SCR. This is its intended operating range.
3. Reference melt points (shared by FWP-25A22F / FI):

100A: Melting time ~10ms

250A: Melting time ~1ms

>500A: Sub-millisecond current-limiting operation

Curve feature: The T-C curve of aR fuse is very steep. It operates extremely fast under large short-circuit current while tolerating low multiple overloads for a long time.

The original T-C diagram is log-log plotted. F and FI of the same current rating share identical melt curves; differences are limited to DC voltage rating and striker construction.

I²t Correction Rule (Mandatory for Semiconductor I²t Coordination Check)

The 530 A²·s value above is total clearing I²t under 700V AC, power factor 0.15.

When operating voltage is lower than 700V AC, actual total clearing I²t reduces, multiplied by correction factor K:

Eg=700Vac → K=1.0

Eg=600Vac → K≈0.82

Eg=480Vac → K≈0.64

DC I²t verification cannot directly reuse AC I²t values. Separate DC curve check is required, especially for FI limited to 500Vdc.

Striker FI Wiring & Fuse Holder Description

JM70100 has two configurations:

1. Standard JM70100: For F version only, no microswitch
2. JM70100 + microswitch module: For FI version. Striker triggers microswitch, typically 1NO+1NC for PLC alarm or trip interlock.

⚠️ The striker provides only a mechanical alarm signal. It does not change fuse protection characteristics or increase breaking capacity.

FWP-25A22F vs FWP-25A22FI Application Selection Table

Coordination & Replacement Guidelines (Engineering Reference)

1. Semiconductor protection check sequence: Device withstand I²t ≥ fuse corrected total clearing I²t
2. Do not replace with gG general-purpose fuses; gG has much higher I²t and may destroy IGBTs.
3. Domestic replacement must satisfy three criteria: 22×58mm size, aR class, 700Vdc rating (if DC circuit), and I²t close to 530. Many domestic aR fuses are only rated 500Vdc and cannot directly substitute F version.
4. Temperature derating: 25A rating is based on 25℃ ambient temperature. Derate to 0.85In typically for 40℃ cabinet ambient.

FWP-25A22FA (FWP-25A22F, aR 700VAC/700VDC, 25A) Application Scope

Core positioning: aR high-speed semiconductor short-circuit fuse, low I²t current-limiting protection for IGBT, SCR, diode power devices, no overload protection.

1. Original Datasheet Listed Applications
2. DC Common Bus

Shared DC bus for multi-drive systems, busbar short-circuit protection. Widely used in energy storage, multi-servo and multi-inverter common-bus schemes. 700Vdc rating supports high-voltage DC bus.

2. DC Drives

DC motor drives, high-power DC speed controllers, short-circuit protection for rectifier bridges and SCR thyristors.

3. Power Converters / Rectifiers

AC-DC rectifier modules, SCR rectifier cabinets, active / passive rectifier units.

4. Reduced Voltage Solid-State Starters

Thyristor circuit short-circuit protection inside solid-state soft starters.

2. Extended Industry Applications

PV & Energy Storage

PV inverter DC side, string inverter power loops

PCS DC bus, post battery cluster power circuit protection (≤700Vdc)

Advantage: 700Vdc rating, strong DC breaking capacity, low I²t, ideal for DC side.

Variable Frequency & Servo Drives

690V class three-phase inverter rectifier and IGBT module protection

High-power servo drives, multi-axis servo DC bus

Crane, metallurgy, conveyor multi-drive common DC bus systems

UPS & Industrial Power Supplies

Industrial online UPS, bidirectional DC/DC converters

High-frequency switching power supplies, electroplating & electrolysis power supplies

High-power SSR solid-state relay circuit protection

Welding & Special Power Supplies

Inverter welding machines, plasma power supplies, high-frequency heat treatment power supplies, IGBT power board protection

Other Power Electronic Equipment

Active Power Filter APF, Static Var Generator SVG power modules

Energy feedback units, braking units (braking IGBT protection)

3. Selection Differentiation (F vs FI)

FWP-25A22F (this model, no striker): Preferred for DC bus >500V, no alarm demand, cost advantage.

FWP-25A22FI (with striker): For AC or DC ≤500V, when fuse alarm, PLC interlock and fault reporting are required.

4. Prohibited Applications
5. General distribution circuits, lighting, heating loads (aR does not protect overload; low overload will not melt and may damage downstream equipment)
6. DC voltage >700V
7. Circuits requiring overload protection without separate thermal / electronic overload protection
8. Direct replacement of gG distribution fuses (gG high I²t risks IGBT destruction)

Eaton Bussmann FWP Cylindrical High-Speed Fuse List (22×58mm series, matching FWP-25A22FA)

Note: A = aR (semiconductor short-circuit, 700VAC/700VDC); G = gR (full range, overload + short-circuit, 690VAC); suffix F = no striker, FI = with striker. FA in trade name refers to original F; AMPxx is only current marking.

1. FWP-xxA22F / FWP-xxA22FI (aR, 700VAC/700VDC, 22×58mm)

⚠️ FI version DC rating derated to 500V. Do not use FI for DC >500V; use F version.

2. FWP-xxG22F / FWP-xxG22FI (gR, 690VAC, 22×58mm, overload + short-circuit)

3. Other FWP Cylindrical Ferrule Sizes
4. 10×38mm: FWP-xxA10F / FWP-xxG10F, current range 4~32A
5. 14×51mm: FWP-xxA14F / FWP-xxG14F, current range 4~50A

Protection class aR / gR same as above; voltage: 700V(aR) / 690V(gR)

4. Other Eaton Bussmann High-Speed Semiconductor Fuse Series (Bolt / Blade Style, High Current)

FWP (bolt-on): 700V, 35~600A, aR, busbar and high-power converter

FWJ: 1000V, high-voltage DC, PV & energy storage high-power

FWH: 1000Vdc high-voltage DC fuse

FWA: 500V, small cylindrical high-speed

FWX: 250V, North American blade high-current

DFJ: Drive dedicated high-speed fuse

5. Matching Fuse Holders (22×58)

JM70100: Standard holder (for F version)

JM70100 + microswitch module: For FI striker version, dry contact alarm output

6. Model Code Summary

FWP Current + A/G + Size Code + F/FI

FWP: Bussmann IEC high-speed semiconductor fuse

A: aR (short-circuit only, IGBT/SCR protection)

G: gR (full range, overload + short-circuit)

22 = 22×58mm; 14 = 14×51mm; 10 = 10×38mm

F: No striker; FI: With striker