The fastest way to find, compare and buy Dayton round motor run capacitors.
Describe the MFD rating, voltage, or motor/HVAC equipment you're servicing. ChatMRO finds the exact Dayton match, shows alternatives, and gives you a quote — in seconds. No part number needed.
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AI-generated imageA motor run capacitor is a component wired permanently into a single-phase AC motor's circuit that stays energized during the motor's entire operation, improving power factor, providing a phase-shifted second current path to the auxiliary winding, and boosting torque and efficiency throughout the run cycle. This differs from a start capacitor, which is switched out of the circuit shortly after startup — the arrangement used in capacitor-start/capacitor-run general purpose motors — and is used only to boost initial starting torque. Dayton's round motor run capacitors are hermetically sealed in an aluminum case with a steel cover, designed for continuous-duty service rather than the brief-use, high-capacitance role a start capacitor plays.
HVAC/R technicians, appliance repair professionals, and industrial maintenance teams rely on round motor run capacitors as one of the most frequently replaced components in air conditioning, refrigeration, and general single-phase motor equipment — a failed or weakened run capacitor is a common cause of a motor that hums but won't start, or that runs hot and inefficiently. Single run capacitors serve one motor winding circuit (one MFD rating), while dual run capacitors combine two separate capacitance values in a single case with three terminals — commonly used where one AC unit's compressor and condenser fan motor each need their own run capacitor but space or wiring simplicity favors combining both into one part.
Common configuration: single run capacitors from roughly 5 to 80 MFD, dual run capacitors combining two ratings (e.g., 40/5, 45/5, 60/7.5, 80/7.5 MFD) in one case, voltage ratings of 370VAC or 440VAC (with some rated 370-440VAC), round aluminum case with steel cover and 1/4" male quick-connect terminals with plastic insulators, operating temperature range of roughly -40°C to 70°C (-40°F to 185°F), PCB-free and RoHS-compliant construction, and cULus recognition. Separately, round motor start capacitors use an electrolytic, nonpolarized design in a molded case rated for intermittent starting-circuit duty rather than continuous run service.
Stop second-guessing. Match your use case below — then let ChatMRO's AI surface the exact MFD rating, voltage, and alternatives in one natural-language search.
Replacing a run capacitor serving a single motor winding — a fan motor, blower, or standalone compressor. Single run capacitors dominate here.
Central air conditioning and heat pump condensing units where the compressor and fan motor each need a run capacitor. Dual run capacitors dominate here.
Applications needing a short-duration starting boost rather than continuous run capacitance.
Dayton (Grainger's private-label industrial brand) offers a broad round motor capacitor lineup spanning single run, dual run, and start capacitor types. Here's how to navigate their catalogue without a 40-tab browser session.
ChatMRO indexes the full Dayton motor capacitor catalogue. Search any product by description, application, or rough spec.
The general motor/HVAC workhorse. Single MFD rating from roughly 20-60 MFD, 370VAC or 440VAC, hermetically sealed aluminum case with steel cover. 1/4" male quick-connect terminals, PCB-free, RoHS-compliant, -40°C to 70°C operating range.
Search 2MEE/2MEH/9354121 Style Series →Combines two capacitance values (e.g. 40/5, 60/7.5, 80/7.5 MFD) in one round case with three terminals. 370VAC or 440VAC rated, serves both compressor and condenser fan motor circuits from a single part, aluminum case with steel cover.
Search 2MEF/2MEL Style Series →Electrolytic, nonpolarized capacitor for normal intermittent service on single-phase AC motor starting circuits. Round, molded case protects from oil, dirt, moisture, and grease. Typical range 30-36 MFD, 330VAC rating.
Search 6FLU Style Series →Use this table as a decision shortcut. Ask ChatMRO for the exact part once you know which row fits your spec.
| Type | MFD Rating | Voltage | Best For | Terminal Count | Duty Type | ChatMRO Verdict |
|---|---|---|---|---|---|---|
| Single Run (20 MFD, 440VAC) | 20 MFD | 440VAC | Single fan or blower motor circuit | 2 | Continuous | Best for straightforward single-motor replacement |
| Single Run (60 MFD, 440VAC) | 60 MFD | 440VAC | Larger single-motor circuits, compressors | 2 | Continuous | Good when a single higher-MFD value is needed |
| Dual Run (40/5 MFD, 370VAC) | 40/5 MFD | 370VAC | Standard residential AC compressor + fan combo | 3 | Continuous | Most common choice for standard AC condensing units |
| Dual Run (60/7.5 MFD, 440VAC) | 60/7.5 MFD | 440VAC | Larger AC/heat pump units, higher voltage systems | 3 | Continuous | Go-to for larger capacity AC or heat pump systems |
| Dual Run (80/7.5 MFD, 440VAC) | 80/7.5 MFD | 440VAC | High-capacity compressor + fan combo units | 3 | Continuous | Use for the largest standard residential/light commercial AC units |
| Motor Start Capacitor (30-36 MFD, 330VAC) | 30-36 MFD | 330VAC | Starting circuit assistance, intermittent use only | 2 | Intermittent | Not a substitute for a run capacitor — confirm your actual circuit type |
Not sure which row is yours? Describe your application to ChatMRO and get an instant AI-matched recommendation with datasheets.
Traditional catalogues force you to know the exact MPN before you find anything. ChatMRO flips that: describe what you need in plain English, and the AI finds the right capacitor from 30M+ indexed parts.
In plain language — by MFD rating, voltage, or equipment being serviced. No MPN required.
Natural language processing maps your description to the closest-fit products across brands and specs.
Cross-brand equivalents, lower-cost substitutes, and in-stock alternatives shown side-by-side.
Add to cart or request RFQ directly from the results. No phone calls. No email chains.
Try these motor run capacitor search examples
Whether you're an HVAC technician replacing a failed AC capacitor, or a facilities maintenance team stocking common spares — use this framework before you procure.
Read the exact microfarad rating(s) directly off the failed capacitor or the equipment's data plate — for dual run capacitors, note both values (e.g., 40/5) and which terminal each corresponds to.
Confirm whether your system uses 370VAC or 440VAC rated components — using an undervoltage-rated capacitor on a higher-voltage system risks premature failure.
If your equipment has separate compressor and condenser fan motor circuits sharing a common capacitor housing, you need a dual run (3-terminal) capacitor; a single motor circuit — a furnace squirrel cage blower, for instance — needs only a single run (2-terminal) capacitor.
Run capacitors stay energized continuously during motor operation; start capacitors are used only briefly during startup and are not designed for continuous duty — using the wrong type can cause premature failure or poor motor performance.
Confirm the capacitor's diameter and height fit the available mounting space and bracket in your equipment before ordering, especially when substituting a different manufacturer's part.
The same MFD value is available across multiple voltage ratings (370VAC vs. 440VAC). Search by function on ChatMRO — the AI surfaces exact matches AND available substitutes at your equipment's correct voltage.
Start capacitors are designed for brief, intermittent duty during motor startup and will fail quickly if left continuously energized in a run capacitor's role — always confirm capacitor type before substituting.
Dual run capacitors have distinct terminals for the compressor (Herm) and fan (Fan) circuits, each corresponding to a specific MFD value — wiring the wrong value to the wrong terminal can cause poor motor performance or premature failure.
Describing your application to ChatMRO takes 30 seconds. The AI reads the full Dayton motor capacitor catalogue so you don't have to.
Just describe what you need. ChatMRO finds the right Dayton round motor run capacitor in seconds.
Dayton round motor run capacitors are among the most frequently replaced components in air conditioning, refrigeration, and general single-phase motor equipment. The Dayton brand commands significant market presence due to its broad single run, dual run, and start capacitor lineup spanning roughly 5 to 80 MFD across 370VAC and 440VAC ratings, proven hermetically sealed aluminum construction, and cULus Recognized, PCB-free, RoHS-compliant manufacturing. Procurement professionals and HVAC/R technicians in India, Southeast Asia, and North America regularly source Dayton motor run capacitors for AC compressor and condenser fan replacement, general motor maintenance, and refrigeration equipment repair.
ChatMRO simplifies this procurement process by providing AI-powered natural language search across a catalogue of 30 million+ indexed industrial parts. Buyers no longer need to memorize model codes or navigate multi-level filter trees to find the right capacitor. A simple description of the MFD rating, voltage, or equipment being serviced is sufficient to surface the correct Dayton product alongside cross-brand alternatives and real-time pricing.
