Troubleshooting 3-Wire DC Motor vs 2-Wire for Ground Service Equipment Repair

Question:

Hello, I need assistance with repairing a piece of ground service equipment at Van Nuys Airport. I hope this request aligns with forum guidelines, as I have seen a similar inquiry regarding DC motor windings. The issue at hand involves an electric aircraft tug previously manufactured by JetPorter, which is now under the ownership of Tronair. Unfortunately, the technical data from the original manufacturer has been lost. The equipment operates on a hydraulic system with a pump and a pump controller that were replaced by a previous mechanic, resulting in the pump malfunctioning. The Curtis-made pump controller has 4 terminals (B+, B-, M-, & A2) for power distribution, while the motor has 2 terminals (T1 marked D1E1 and T2 marked A2E2). It is evident that the current motor is not suitable for the 72-volt system as it is labeled for 48 volts. Before acquiring a new motor, it is crucial to determine the correct winding configuration. It is assumed the new motor should be a 3-wire, unidirectional motor wired to B+, M-, and A2 on the speed controller outputs. When connected to B+ and A2, the speed controller does not activate the motor but does provide 59 volts to open the ground path on M-. Any guidance on the proper winding for this motor would be greatly appreciated, as the equipment's functionality is vital for airport operations. Thank you in advance for any assistance provided.

Top Replies

The electrohydraulic transmission system may rely on the hydraulic component for speed regulation, while the electric motor operates at a consistent pace. In this case, only 2 wires may be necessary for operation. Are there any comparable systems in the vicinity that we can observe to better understand its functionality?

If you're looking to set up a speed controller for a permanent magnet motor using armature wire, seek advice from golf cart repair forums. These forums hold a wealth of information on DC motors and controllers, with enthusiasts sharing their insights on making or modifying speed controllers and motors. In the industrial sector, DC motors were phased out in favor of VFDs due to their cost-effectiveness. Explore these forums to tap into the tribal knowledge for similar projects.

Thank you for your contribution.

Are you looking for assistance with a custom motor drive system? Most equipment typically runs on 48v, but custom systems can use different voltages. Hydraulic pumps typically operate at a fixed speed, while DC motors have various lead configurations. Armature (A1/A2), field (F1/F2), and series field (S1/S2) connections determine motor power. Varying field current controls speed, and changing polarity controls direction. If you're uncertain about your motor system, consider replacing both the motor and drive with more standard options. Figuring out a custom system without documentation may be challenging, but using an ohm meter to test the windings could provide insight.

Thank you for your response, I appreciate it. Tronair has acquired the company that created the electric tug JetPorter, and there seems to be limited information available on the 72-volt system. They now offer a comparable 48-volt unit, which was sold to a previous mechanic who was unable to get it running. The mechanic also purchased a 1204m speed controller, for which I have attached literature and pictures of my DC motor terminals. The equipment is a combination of parts from two different machines since the 72-volt system is no longer in production and lacks technical support. Thank you for your assistance.

Your issue seems rather complex but I'll try to provide some advice based on your description. It's evident that the 48-volt motor is not ideal for a 72-volt system, causing incompatibility. As you seek to rectify this, a good start would be to identify a 72-volt motor with the same output specifications as the original motor. The winding configuration should then correlate directly with the voltage of replacement motor. Bear in mind that when connecting to B+ and M-, it should provide sufficient power to operate - the A2 terminal will then be used as a return path to the controller. If you're still having issues with the speed controller not activating, it could hint to a deeper wiring issue or possibly even a controller fault. I would recommend consulting Tronair's customer service or an experienced aircraft ground equipment technician for more specific insight tailored to your situation. Stay safe!

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Frequently Asked Questions (FAQ)

FAQ: 1. What is the difference between a 3-wire DC motor and a 2-wire DC motor?

Answer: Answer: A 3-wire DC motor typically has an additional wire for feedback or control purposes, while a 2-wire DC motor has only two wires for power input.

FAQ: 2. How can one determine the correct winding configuration for a DC motor?

Answer: Answer: To determine the correct winding configuration for a DC motor, it is essential to refer to the motor's specifications or consult technical documentation. In the absence of such information, testing different configurations with a multimeter or seeking assistance from a professional may be necessary.

FAQ: 3. Can a DC motor labeled for a lower voltage be used in a system with a higher voltage?

Answer: Answer: It is generally not recommended to use a DC motor labeled for a lower voltage in a system with a higher voltage, as this can lead to overheating, reduced efficiency, and potential damage to the motor. It is advisable to use a motor that is rated for the system voltage to ensure proper operation and longevity.

FAQ: 4. How should a 3-wire DC motor be wired to a pump controller for proper operation?

Answer: Answer: A 3-wire DC motor should typically be wired to the appropriate terminals on the pump controller according to the manufacturer's guidelines or technical specifications. In this case, the motor may need to be connected to specific terminals such as B+, M-, and

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