Decoding the 056b17drr70036a1 Leeson Motor Number
The string 056b17drr70036a1 is a Leeson Electric motor model number, and each part of it tells you something specific about the motor's design and capabilities. Leeson is a US-based manufacturer of industrial and fractional horsepower motors, and their numbering system is consistent enough that you can pull real information from the code without needing to call the factory.
Breaking this number down: the first three digits (056) identify the motor frame size and general category. The letter that follows (b) indicates the voltage and phase configuration. The next two digits (17) relate to the motor's horsepower and speed rating. The letters after that (drr) describe the motor's duty cycle and thermal protection. The final digits (70036a1) are the sequential part number that distinguishes this specific variant from similar motors in the same family.
Understanding what you have matters because it tells you whether a replacement motor will actually fit your equipment, whether it will deliver the right amount of power, and what kind of electrical connection it needs. A motor that looks similar but has a different code may not work in your process, even if it bolts to the same mounting holes.
Key Takeaways
- The 056b17drr70036a1 code breaks into frame size (056), voltage/phase (b), horsepower/speed (17), duty cycle (drr), and part number (70036a1).
- Leeson's numbering system is standardized, so you can use the code to find exact specifications without a manual or the original documentation.
- When replacing this motor, you need to match the frame size, voltage, phase, and horsepower — a motor with a different code may not fit or perform correctly.
- Leeson publishes cross-reference charts and specification sheets online and through industrial suppliers, so you can verify compatibility before ordering.
What the Frame Size Code Tells You
The first three digits, 056, identify the motor's frame size. In Leeson's system, this number corresponds to the physical dimensions of the motor housing and the bolt pattern used to mount it. Frame size matters because your equipment was designed to accept a motor with specific mounting holes in specific locations.
A frame 056 motor will bolt to the same mounting surface as any other frame 056 motor from Leeson, but it will not fit a frame 048 or frame 063 process. If you try to force a different frame size into your equipment, the bolt holes will not align, or the motor will protrude too far and hit other components. The frame size also correlates roughly with the motor's overall length and weight, so it affects how much space you have to work with.
You can find the exact dimensions of a frame 056 motor in Leeson's specification sheets, which are available through industrial electrical suppliers or directly from Leeson's website. The sheet will show you the mounting face dimensions, the shaft diameter, and the overall length — all the information you need to confirm that a replacement motor will physically fit.
Voltage, Phase, and the Letter Code
The letter b in the model number encodes the motor's electrical configuration. Leeson uses different letters to indicate whether the motor is single-phase or three-phase, and what voltage it runs on. Single-phase motors are common in small equipment and home workshops; three-phase motors are standard in industrial settings where three-phase power is available.
The voltage matters because your equipment's power supply delivers a specific voltage — usually 115V, 230V, or 460V for industrial motors. A motor rated for 230V will not run correctly on 115V, and running it on the wrong voltage can damage the motor or create a fire hazard. The phase matters because a three-phase motor cannot run on single-phase power without additional equipment, and a single-phase motor will not work on a three-phase circuit.
If you do not have the original documentation, you can look at the equipment's nameplate or the power cord and outlet to determine what voltage and phase you have. Then cross-reference that information against Leeson's specification sheets to confirm that the 056b17drr70036a1 matches your power supply. If it does not, you will need a different model number.
Horsepower and Speed in the Middle Digits
The digits 17 indicate the motor's horsepower rating and its speed in revolutions per minute (RPM). Leeson motors come in fractional horsepower sizes — typically 1/4, 1/3, 1/2, 3/4, 1, 1.5, 2, and 3 horsepower — and in standard speeds like 1200 RPM, 1800 RPM, or 3600 RPM for 60 Hz motors.
The horsepower tells you how much mechanical work the motor can do. If your equipment requires a 1 horsepower motor and you install a 1/2 horsepower motor instead, the smaller motor will overheat and fail because it cannot handle the load. Conversely, installing a larger motor than necessary wastes energy and costs more upfront, though it will not damage the equipment.
The speed affects how fast the motor's shaft turns and, by extension, how fast your equipment operates. A pump, fan, or conveyor belt designed for 1800 RPM will not work correctly at 3600 RPM — it may move material too fast, create excessive vibration, or damage bearings. Always match the speed rating to what your equipment was designed for.
Duty Cycle and Protection Features
The letters drr describe how the motor is designed to run and what thermal protection it includes. Duty cycle refers to whether the motor is meant to run continuously (24 hours a day) or intermittently (on and off throughout the day). A motor rated for intermittent duty will overheat if you run it continuously, and a continuous-duty motor is overkill for equipment that only runs a few hours a week.
The code also indicates whether the motor has built-in thermal overload protection — a device that shuts the motor off if it gets too hot. This protection is a safety feature that prevents fires and extends the motor's life by preventing damage from overheating. Some applications require this protection by code; others do not. Leeson's specification sheets will tell you exactly what protection the 056b17drr70036a1 includes.
Finding Replacement Parts and Cross-References
When you need to replace a Leeson motor, you have several options for finding the right part. The most direct route is to contact an industrial electrical supplier — companies like Grainger, MSC Industrial, or local electrical distributors stock Leeson motors and can look up the 056b17drr70036a1 by model number. They can confirm that the motor is in stock, provide the current price, and tell you the lead time for delivery.
Leeson also publishes cross-reference charts that show which of their motors are equivalent to motors from other manufacturers. If your equipment originally had a motor from a different brand and you want to replace it with a Leeson, these charts help you find the closest match. The charts are available on Leeson's website and through their technical support line.
Before you order, verify that the replacement motor matches the original on frame size, voltage, phase, horsepower, and speed. If any of these specifications differ, the motor may not fit or may not perform correctly. Most suppliers will let you return a motor if it is the wrong model, but it is faster and cheaper to get it right the first time.
When the Model Number Does Not Match Your Equipment
Sometimes you will find that the motor in your equipment does not have a Leeson label, or the label is too worn to read. In that case, you can measure the frame size and mounting dimensions, check the voltage and phase on the power cord, and look for any horsepower or speed information on the equipment's nameplate. With those details, you can search Leeson's catalog or ask a supplier to find a motor that matches.
If your equipment was originally fitted with a motor from a different manufacturer — Marathon, Baldor, or Dayton, for example — you can still use a Leeson replacement as long as the frame size, voltage, phase, horsepower, and speed are the same. The motor will bolt on and run correctly even if the brand is different. Some equipment designers specify a particular brand for warranty or performance reasons, so check your equipment's manual if you have one.
Frequently Asked Questions
Can I use a different Leeson motor if the frame size is the same?
No. Frame size is necessary but not sufficient. The motor must also match on voltage, phase, horsepower, and speed. A motor with a different voltage or horsepower will not work correctly, even if it bolts to the same holes. Always cross-reference all the specifications before ordering.
What does the last part of the model number (70036a1) mean?
That is the sequential part number that distinguishes this specific motor variant from others in the same family. It accounts for small design changes, manufacturing updates, or regional variations. You do not need to memorize it, but it ensures you get the exact motor Leeson made, not a close approximation.
Where can I find the full specification sheet for this motor?
Leeson publishes specification sheets on their website, and most industrial electrical suppliers (Grainger, MSC, local distributors) have them in their databases. You can also call Leeson's technical support line with the model number and they will email or mail you the sheet. The sheet includes dimensions, electrical ratings, and performance curves.
Can I replace a three-phase motor with a single-phase motor of the same horsepower?
No. Three-phase and single-phase motors are not interchangeable, even if the horsepower is the same. Your power supply must match the motor's phase. If you need to switch from three-phase to single-phase (or vice versa), you need a different motor and possibly an electrician to rewire your equipment.
What if I cannot find the exact model number anywhere?
Contact Leeson directly with the model number and any other information from the motor's nameplate. Their technical support team can help you locate the motor in their archives or find the closest current equivalent. You can also bring the motor itself to a local electrical supplier — they can often identify it by sight and find a replacement.