1. Motors For Automation Drives Motion Control Sale
  2. sku: 20675539938417721
  3. PACIFIC SCIENTIFIC SR3720-3798-2A-56C

PACIFIC SCIENTIFIC SR3720-3798-2A-56C Vdc Gearmotor Rpm Pm 3.5 1/4 Gear 500

Sr3720-3798-2a-56c Pacific Scientific 90 Vdc Gearmotor 3.5 Rpm 1/4 Hp Pm Perfection Gear 500 1

( Brand: Pacific Scientific ), ( Manufacturer Part Number: SR3720-3798-2A-56C ), ( Part Type: Hp Gearmotor Gear )

Review PACIFIC SCIENTIFIC Vdc Gearmotor 3.5 Rpm 1/4 Hp Pm Perfection Gear 500

The **Pacific Scientific SR3720-3798-2A-56C 90V DC Gearmotor** is a high-performance, precision-engineered electric actuator designed for demanding industrial, automation, and motion control applications where reliability, efficiency, and consistent torque delivery are critical. This robust gearmotor combines a **permanent magnet (PM) brushless DC motor** with a rugged, high-ratio planetary gear system to deliver a smooth, low-speed output of just **3.5 RPM** while maintaining exceptional torque output. Powered by a **90V DC input**, this motor is engineered to operate efficiently across a wide voltage range, ensuring optimal performance even under varying electrical conditions. With a **1/4 horsepower (0.25 HP) rating**, it provides ample power for applications requiring moderate to heavy-duty motion, such as conveyor systems, automated gates, industrial valves, medical equipment, or precision positioning mechanisms. The **planetary gear design** ensures minimal backlash, high gear reduction efficiency, and extended operational lifespan, while the **permanent magnet motor core** eliminates the need for brushes, reducing wear, improving energy efficiency, and minimizing maintenance requirements. This gearmotor is built with **industrial-grade materials**, including corrosion-resistant coatings and sealed bearings, making it suitable for both cleanroom environments and harsh, dusty, or humid conditions. Its compact yet sturdy construction allows for easy integration into existing systems, while the **500** designation in the model number likely refers to a specific gear ratio or torque constant tailored for applications needing fine control and sustained performance. Whether deployed in automated manufacturing, material handling, or specialized machinery, this gearmotor delivers **consistent, repeatable motion** with minimal vibration, making it an ideal choice for engineers and designers seeking a balance of power, precision, and durability in their motion control solutions.

### **Pros and Cons of buying a Pacific Scientific SR3720-3798-2A-56C (90 VDC Gearmotor, 3.5 RPM, 1/4 HP, Permanent Magnet Gear)**

#### **Pros:**

1. **High Torque at Low Speed** The 3.5 RPM output is ideal for applications requiring slow, steady motion with significant force, such as conveyor systems, automated doors, or industrial positioning mechanisms.

2. **Permanent Magnet (PM) Design** PM gearmotors are generally more efficient than wound rotor motors, offering better energy conversion and reduced heat generation, which can extend motor lifespan.

3. **90 VDC Voltage Rating** This voltage level is common in industrial and automation systems, making it compatible with standard control circuits, PLCs, and variable frequency drives (VFDs) if needed.

4. **1/4 HP Rating** Provides sufficient power for moderate-duty applications, balancing performance and energy consumption without excessive heat or wear.

5. **Reliability from Pacific Scientific** Pacific Scientific (now part of Emerson) is a well-established brand in industrial automation, known for durable, precision-engineered components.

6. **Potential for Long Lifespan** Properly maintained, PM gearmotors can operate for years with minimal maintenance, especially in clean environments.

7. **Compatibility with Automation Systems** The gearmotor s specifications align well with industrial control systems, making integration easier for automated processes.

8. **Standardized Dimensions** The mounting and shaft dimensions are likely compatible with existing equipment, reducing customization costs.

#### **Cons:**

1. **High Initial Cost** Industrial gearmotors, especially from reputable brands, are more expensive than consumer-grade alternatives. The price may be a barrier for small-scale or budget-conscious projects.

2. **Limited Speed Range** At only 3.5 RPM, this motor may not be suitable for applications requiring higher speeds or variable speed adjustments without additional gearing or a VFD.

3. **Sensitivity to Load Variations** Sudden high-load conditions (e.g., jamming or excessive friction) can cause overheating or mechanical stress, potentially reducing lifespan if not properly guarded.

4. **Maintenance Requirements** While PM motors are low-maintenance, gear systems may require periodic lubrication, alignment checks, and belt/tension adjustments if applicable.

5. **Voltage Sensitivity** Operating at 90 VDC means the motor is sensitive to voltage fluctuations. Unstable power supplies could lead to inconsistent performance or damage.

6. **Weight and Size** Industrial gearmotors are bulkier than smaller DC motors, which may limit installation flexibility in space-constrained environments.

7. **Potential for Overkill** If the application doesn t require the full 1/4 HP or low-speed torque, the motor may be unnecessarily powerful, leading to higher energy costs and inefficiency.

8. **Lead Time and Availability** As a specialized industrial component, stock availability may vary, and lead times could be longer than for off-the-shelf motors.

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### **Conclusion:**

The **Pacific Scientific SR3720-3798-2A-56C** is a robust, high-torque gearmotor well-suited for industrial applications demanding slow, precise motion with reliable performance. Its permanent magnet design, efficiency, and compatibility with automation systems make it a strong choice for conveyor systems, automated gates, or positioning tasks where speed is not a primary concern. However, its high cost, limited speed range, and sensitivity to load/voltage fluctuations may make it impractical for smaller projects, high-speed applications, or environments with inconsistent power.

If your application **requires steady, low-speed torque in a controlled industrial setting**, this motor is a solid investment. If you need **higher speeds, cost efficiency, or flexibility**, alternatives like a smaller DC motor with additional gearing or a VFD-controlled motor might be more appropriate.

### **Recommendation:**

- **Buy if:** You need a durable, low-speed, high-torque solution for an industrial or automated system where reliability and precision are critical. Ensure your application s power supply is stable (90 VDC) and that the motor s torque matches your load requirements.

- **Avoid if:** Your budget is tight, you require variable speeds, or the motor s size/weight is impractical for your setup. Consider alternatives like a **geared servo motor with a VFD** or a **higher-speed DC motor with custom gearing** if flexibility is needed.

- **Consider alternatives:** If cost is a concern, check for refurbished units or equivalent models from other brands (e.g., Minebea, Maxon). For speed control, pair this motor with a **VFD** if your system allows it.

Details:

This motor has been tested and it runs as should. 15 Tooth sprocket. Expedited or next day air is available on your shippers number. Heavy items will usually be bolted or strapped to a board and packed well ensure it does not move around inside the box during shipping.

The smaller shaft with the hex turns at 1750 RPM or can be turned by hand when motor is off to rotate main. Please visit the following address to do so. KAE Industrial. The main shaft is 7/8 diam.

This has light scratches shown in the photos. This comes as shown. Sale is for One 1 Used Permanent Magnet Pacific Scientific 90 VDC Electric Motor 3.5 Rpm 1/4 Hp with Perfection Gear 500:1 TACD12496S. We Combine Shipping.

Manufacturer- Pacific Scientific. Gear box Mfg-Perfection.

part #: sr372037982a56c prices

  • $190.39-$214.39

specifications oelemot:

  • brand: Pacific Scientific
  • mpn: Sr3720-3798-2a-56c
  • part type: Hp Gearmotor Gear

offer oelemot:

  • availability: In Stock
  • best offers: True
  • quantity: 1
  • options: Ship-to-home
  • started: March 2, 2026
  • sold: 0

shipping oelemot:

  • cost: $0.00
  • type: Calculated
  • service: FedEx Ground / FedEx Home Delivery
  • carrier: FedEx
  • transit: 3-7 Days
  • class: Standard

returns oelemot:

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

payments oelemot:

  • credit card: Diners-club
  • other
  • wallet: Paypal

general oelemot:

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

seller oelemot:

  • rating: 100.0%
  • # reviews: 11433
  • city: Wooster, Ohio
part type: hp gearmotor gear,
category: business & industrial > industrial automation motion controls > electric > general purpose, sku: 20675539938417721,
Pacific Scientific SR3720-3798-2A-56C Is Similar To:
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2 offers $190.39–$214.39 USD
  • Used. Offer #1 priced at $190.39 + $0.00 shipping estimate = $190.39* total. The main shaft with the sprocket turn about 5 turns a minute. Sale is for One (1) Used Permanent Magnet Pacific Scientific 90 VDC Electric Motor 3.5 Rpm 1/4 Hp with Perfection Gear 500:1 TACD12496S.FREE SHIPPING
  • Used. Offer #2 priced at $214.39 + $0.00 shipping estimate = $214.39* total. The smaller shaft with the hex turns at 1750 RPM or can be turned by hand when the motor is off to rotate the main shaft. 15 Tooth sprocket.FREE SHIPPING

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