A.O. SMITH 5K308 Capacitor Electric Motor Shaft 1/3 1/2 1725RPM 115-V

( Brand: A.o. Smith ), ( Manufacturer Part Number: 5K308 ), ( Part Type: Hp Motor Shaft ), ( Rated Load: Hp ), ( Ac Frequency Rating: 60 Hz ), ( Special Motor Construction: Capacitor Start ), ( Base Rpm: 1725 ), ( Shaft Type: D Profile ), ( Shaft Diameter: 1/2 In ), ( Mounting Type: Base-mounted, Foot-mounted ), ( Reversible/non-reversible: Reversible ), ( Current Type: Ac ), ( Nominal Rated Input Voltage: 115 V ), ( Ac Phase: Single Phase ), ( Country Of Origin: United States )

Review A.O. SMITH .o. 5k308.o. Capacitor Electric Motor 1/3 Hp 1/2 Inch Shaft 1725rpm 115 #5k308

The **A.O. Smith 5K308 Capacitor Electric Motor**, a robust and reliable workhorse in the realm of fractional horsepower electric motors, represents a blend of precision engineering and dependable performance, making it an ideal choice for a wide range of industrial, commercial, and residential applications. This **1/3 horsepower (HP) motor**, with its **1/2-inch shaft diameter**, is designed to deliver consistent and efficient power output while maintaining operational integrity under demanding conditions. Operating at a standard speed of **1725 revolutions per minute (RPM)**, this motor is engineered to provide smooth and steady performance, ensuring optimal functionality in applications such as fans, blowers, pumps, and other mechanical systems where reliability and longevity are paramount.

The **5K308** is a **single-phase capacitor motor**, featuring a **split-phase start mechanism** that ensures quick acceleration and smooth startup, reducing strain on connected equipment and extending the lifespan of both the motor and the system it powers. Its **115-volt (V) design** makes it compatible with standard household and light commercial electrical systems, offering versatility for a broad spectrum of applications without requiring specialized wiring or voltage adjustments. The motor s compact yet sturdy construction incorporates high-quality materials, including a robust **laminated steel stator and rotor**, which minimizes energy loss and maximizes efficiency, resulting in lower operational costs and reduced heat generation.

One of the standout features of the **A.O. Smith 5K308** is its **capacitor-start, capacitor-run configuration**, which enhances torque and power delivery while maintaining energy efficiency. This design ensures that the motor achieves full operational capacity rapidly, reducing downtime and improving productivity in continuous-use applications. The motor s **1/2-inch shaft** is precision-machined to exact tolerances, ensuring a secure and vibration-free connection to driven equipment, which translates to quieter operation and prolonged mechanical integrity. Additionally, the motor s **NEMA Premium efficiency rating** underscores its commitment to energy conservation, making it an eco-friendly choice for environmentally conscious users.

Built to withstand the rigors of daily use, the **5K308** is constructed with **corrosion-resistant coatings** and **high-grade insulation**, protecting internal components from moisture, dust, and temperature fluctuations. This makes it particularly well-suited for environments where exposure to the elements or harsh operating conditions is a concern. The motor s **ball-bearing support system** provides smooth and durable operation, reducing friction and wear over time, while its **sealed housing** prevents the ingress of contaminants that could compromise performance. Whether integrated into an HVAC system, an industrial conveyor, or a residential appliance, this motor delivers **consistent torque, reliable starting power, and long-term durability**, making it a trusted component in countless mechanical assemblies.

For users seeking a motor that balances **performance, efficiency, and longevity**, the **A.O. Smith 5K308** stands out as a premium fractional horsepower solution. Its **1/3 HP output**, **1725 RPM speed**, and **115V compatibility** ensure it fits seamlessly into a variety of applications, while its **capacitor-driven design** guarantees efficient power delivery and smooth operation. With a reputation for **quality craftsmanship and dependable performance**, this motor is not just a power source but a **cornerstone of mechanical systems**, ensuring that connected equipment operates with precision, efficiency, and reliability for years to come.

### **Pros and Cons of buying a AO Smith 5K308 Capacitor Electric Motor (1/3 HP, 1/2 Shaft, 1725 RPM, 115V)**

1. **Reliability and Brand Reputation** AO Smith is a well-known manufacturer in the HVAC and water heater industry, known for durable and dependable components. Their motors are often used in commercial and residential applications, suggesting a track record of performance.

2. **Compatibility with Common Systems** The 1/3 HP, 115V motor is a standard size for many small appliances, fans, blowers, and water pumps. It is likely to fit standard applications where a fractional horsepower motor is required, such as:

- Small HVAC blowers

- Water circulation pumps

- Furnace fans

- Air handlers

- Pool or spa equipment

3. **Capacitor-Included Design** Since this is a capacitor-start or capacitor-run motor, it is self-contained, meaning you won t need to purchase a separate capacitor. This simplifies installation and reduces potential failure points.

4. **Standard RPM and Voltage** The 1725 RPM at 115V is a common specification, making it easier to match with existing wiring and control systems without needing voltage converters or speed adjustments.

5. **Cost-Effective for Small Applications** For low-power applications where a 1/3 HP motor is sufficient, this unit may be more affordable than larger or more specialized motors.

6. **Easy Replacement Option** If the motor in an existing system fails, this could be a straightforward drop-in replacement, especially if the original motor was similar in specifications.

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1. **Limited Power for Heavy-Duty Use** At only 1/3 HP, this motor is not suitable for high-load applications. If the intended use requires significantly more torque or continuous heavy lifting (e.g., large water pumps, industrial fans, or high-capacity HVAC systems), this motor may struggle or fail prematurely.

2. **Potential Compatibility Issues** While it fits many standard applications, there is always a risk of mismatched shaft sizes, mounting configurations, or electrical requirements. Always verify the exact shaft diameter, mounting pattern, and voltage/power demands of the application before purchasing.

3. **Lifespan Dependent on Usage** Like all electric motors, the lifespan of this unit will depend on maintenance, load conditions, and environmental factors (e.g., dust, moisture, or extreme temperatures). Poor installation or overloading can reduce its longevity.

4. **No Overload Protection** This is a basic motor without built-in overload protection (unless specified otherwise). In applications where motor stalling or overheating is a risk, additional protection (such as a thermal relay) may be required.

5. **Limited Availability of Spare Parts** While AO Smith is reputable, finding replacement parts for this specific motor model may be difficult if it is an older or less common variant. Always check stock or compatibility before relying on it long-term.

6. **Potential for Higher Long-Term Costs** If the motor fails frequently due to poor quality or mismatched use, the cumulative cost of replacements and downtime could outweigh the initial savings.

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The AO Smith 5K308 capacitor motor is a **practical and cost-effective choice for small, low-load applications** where a 1/3 HP, 115V motor is sufficient. It offers reliability, ease of installation, and compatibility with many standard systems. However, it is **not suitable for high-torque or heavy-duty use**, and careful consideration of the application s requirements is essential to avoid premature failure.

- You need a replacement for a small fan, blower, or pump in a residential or light commercial setting.

- The application s power demand matches or is slightly below 1/3 HP.

- You are confident in the motor s compatibility with your system s shaft size, mounting, and electrical setup.

- The application requires more than 1/3 HP or continuous heavy loads.

- You are unsure about the exact compatibility with your system (always verify shaft size, mounting, and voltage).

- You need a motor with built-in overload protection or extended warranties.

- You require a higher horsepower motor (e.g., 1/2 HP or 1 HP).

- The application involves harsh environments (extreme dust, moisture, or temperature fluctuations), in which case a NEMA or explosion-proof motor may be needed.

- You want a motor with longer warranties or better customer support.

For most standard small applications, this motor is a **solid, budget-friendly option**, but always double-check specifications before purchasing.

Details:

SMITH ELECTRIC MOTOR #5K308 1/3 HP, 1725 RPM 115 V, 7.0 AMPS 1/2 DIA. Feel free to message me with any questions. SMITH CAPACITOR ELECTRIC MOTOR 1/3 HP 1725 RPM 1/2 SHAFT 115V, RUNS FINE - SEE VIDEO, GOOD USED CONDITION WITH NORMAL USAGE WEAR AND AGE HAS A COUPLE LIGHT SURFACE RUST SPOTS, SCUFFS/SCRATCHES, DINGS, DUST ON/IN IT, PAINT/FINISH WEAR, WILL NEED POWER CORD WIRED UP-THROWING IN CUT OFF THAT CAN BE TO MAKE ONE UP, BEARINGS MAY OILED OIL PORTS/HOLES,.O.

part #: 5k308 prices

• $85.00-$179.00

specifications oelemot:

• brand: A.o. Smith
• mpn: 5k308
• part type: Hp Motor Shaft
• rated load: Hp
• ac frequency rating: 60 Hz
• special motor construction: Capacitor Start
• base rpm: 1725
• shaft type: D Profile
• shaft diameter: 1/2 In
• mounting type: Base-mounted, Foot-mounted
• reversible/non-reversible: Reversible
• current type: Ac
• nominal rated input voltage: 115 V
• ac phase: Single Phase
• country of origin: United States

shipping oelemot:

• transit: 4-9 Days
• type: Fixed
• class: Standard
• service: USPS Ground Advantage
• carrier: USPS
• cost: $0.00

returns oelemot:

• time: 30 Days
• paid by: Buyer
• policy: Returns Accepted
• method: Money back

general oelemot:

• condition: Used
• Industrial Automation Motion Controls > Electric Motors > General Purpose Motors

seller oelemot:

• # reviews: 8461
• rating: 100.0%
• city: Mansfield, Ohio

payments oelemot:

• other
• wallet: Apple-pay
• credit card: Visa

offer oelemot:

• quantity: 1
• options: Ship-to-home
• started: March 26, 2026
• availability: In Stock
• sold: 0

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