9-Step Guide to Completing the Generic Servo Motor Datasheet

Overview

This guide provides a test procedure designed to be followed on every permanent magnet brushless servo motor. It is important to complete a datasheet for every motor you test. This procedure is designed to be followed in order from steps 1-9. Do not alter the motor’s feedback device position until it has been properly documented. Do not run test a motor prior to documentation and testing. Take pictures and save them into a folder with this completed document along with your Athena test reports and memory data. 

This guide is intended to be used with the “Generic Servo Motor Datasheet” attached at the bottom of this article. (Current datasheet revision: 05/01/2024)

The information gathered in each step will be entered into the blank datasheet. Please reference the picture at the bottom of this article for help on where each step gets entered into the datasheet. Video links are also present for each step of the guide. 

Procedure

1. Document the motor nameplate and connector data

Submit a “Support Request” for quick help identifying the required cabling and pinouts. You may also reference our “Parts by Manufacturer” page to find a matching feedback or power test cable. Next, document the details below.

1.  Manufacturer (Mfr)
2.  Model number (type or part number)
3.  Serial number
4.  Current rating (Amps) 
5.  Voltage rating
6.  RPM rating
7. Test Cable and Connector Data
   1. Add the TI-xxxx test cable number and adapter module (if needed). 
   2. Include pictures of power and feedback connectors (or terminals) with pins clearly labeled.
   3. Label pin #, function, and wire color. The test cable datasheet or motor’s technical manual often contains this info.
   4. Copy any connector part info written on feedback/power connectors. 

Video Reference: "How to Submit a Support Request"

2. Document the motor winding resistances with an ohmmeter

1. Take three readings, measuring from U-V (U phase), then V-W (V phase), then W-U (W phase). Include the resistance values in the function portion of the power connector pinouts for each phase. 
2. Measure the resistance from any of the 3 phases to Ground and make sure there is no continuity.

Do not proceed with applying power to the windings if there any direct shorts to ground or major imbalances in the resistance readings. Unbalanced readings could indicate defective windings or poor connections either internally or externally to the motor. 

Video Reference: "Checking Motor Winding Resistances"

3. Determine the number of motor poles

1. Unlock the motor brake if equipped.
2. Set the DC lockup supply to half the rated current (Amps) of the motor, at 12VDC.
3. Lock the motor with +U-V and mark the position of the motor shaft relative to the motor frame.
4. Unlock the motor, rotate the shaft to a new position, and relock the motor with the same +U-V lockup.  Again, mark the position of the shaft. If it returns to the same position as before, try rotating a bit further. 
5. Find all possible +U-V lockup positions around the motor. This is the number of pole pairs.
6. Multiply the pole pairs by 2 to get the total number of motor poles.

Video Reference: "Determine the Number of Motor Poles"

4. Determine the forward direction of the motor

1. Lock the motor with +U -V and note the motor shaft location. This is now the starting point. It does not matter what direction the shaft turned getting to this starting point.
2. Change lockup polarity to +U -W. Note the motor shaft direction of rotation (as viewed from the motor shaft end).
3. Perform 2 or 3 more lockups in the forward direction to verify motor rotation is either CW or CCW. The forward direction lockup order is listed on the TI-5260 lockup box and below for reference.
   1. +U-V     2. –W+U     3. +V-W     4. –U+V     5. +W-U     6.–V+W

Video Reference: "Determine the Motor Forward Direction"

5. Determine the KE Rating (V AC RMS L-L/KRPM)

Back-drive the motor at 1,000rpm and record the generated AC voltage (RMS) coming from the windings using line-to-line connections (U-v, V-w, and W-u). This voltage should be close to equal across all three windings. If not, there may be problems with the motor windings or magnets. An oscilloscope can be used to see the waveform, which if distorted could indicate issues with the magnets or windings.

The Ke rating can be also be used to determine approximately how fast the motor will run on the TI-3000JX system and your AC line voltage to the amp using this formula: 
MaxRPM = 1000 RPM * (VACsupply / Ke)

For example: a very large motor with Ke of 240V will run at a max speed of around 500 rpm using an amplifier with 120V AC supply, and around 1,000 rpm using a 240V AC supply.

Video Reference: "Determine the Ke Rating"

6. Test and Document the Feedback Device

1. Connect the feedback device to the TI-5000JX for testing.
   1. Choose the correct selection in the ‘Select Feedback’ menu of Athena.
   2. Enter the correct number of motor poles in Data Display to receive valid electrical angles. 
   3. Perform the various on-screen tests. There are different tests depending on the feedback selected.  
2. Enter feedback details into the datasheet including any feedback nameplate data. This generic datasheet includes fields for many types of feedback devices. Deleting unused fields may help avoid confusion.
   1. If selecting GENERIC INCREMENTAL ENCODER, first go to the Count Test to find out how many counts/rev are on the encoder. If you do not know, simply enter any count to get into the Count Test. The counts/rev will be listed in the rightmost column of this test, regardless of what count is currently entered into the system. The correct counts/rev needs to be entered into the software using the ‘Enter Counts/Rev’ button under the Generic Incremental Encoder menu selection. Make sure you can perform a Count Test without any count errors before recording the alignment. Incremental encoders may also have commutation pulses and they need to be tested and documented as well (see step 8).
      
      Video Reference: "TI-5000JX Commutation Testing and Alignment"
      
      
   2. If selecting RESOLVER feedback, make sure to document the number of speeds of the resolver (how many times through 0 degrees in one turn) as well as the frequency, voltage, phase offset, and resulting vector level. Enter the “Resolver Setup” menu to adjust these values and get the Vector Level into the green. Adjust your frequency up or down trying to get the Phase Offset box as close to 0 as possible. The Vector Level should stay constant (within 10%) during the entire rotation on a good resolver.   
      
      Video Reference: "TI-5000JX Resolver Setup, Testing, and Alignment"
      
      
   3. If selecting a SERIAL ENCODER, check Data Display for alarms or errors. Perform the Count Test and Memory Test if applicable. Document the correct number of serial single-turn counts/rev and multi-turn counts (if applicable). Save encoder memory data (if applicable) and note the file’s storage location. Some serial encoders also have incremental outputs in addition to the serial output, and those need to be documented as well. List their number of counts and make sure they have the proper signal output.
      
      Video Reference: "TI-5000JX Hiperface and Indramat Electronic Alignment"

7. Document the Forward Direction of Feedback Device

Looking from the motor shaft end, rotate the motor and watch the feedback angles. The forward direction of the feedback is the direction in which the angles increase (either CW or CCW)

Video Reference: "Determining the Feedback Forward Direction"

8. Document the Current Alignment of Feedback Device
Always record two different lockups (+U-V and +U-W) on every feedback device. This help ensure proper rotation when re-checking alignment. 

1. For encoders, lock the motor with +U-V and record the electrical angle at this point. Make sure your motor poles are set correctly. If so, the electrical angle will repeat at each +U-V lockup position around the motor. Record all +U-V lockups and all +U-W lockups.
2. For Hall effects and commutation signals, record the H (high) and L (low) states as well as the toggle point transition (H/L or L/H) using the forward direction of the motor as the transition reference. If no toggle point exists directly at +U-V, try the neutral position lockup +U-V-W and look for a toggle. If there is no toggle at either lockup type, the feedback may be misaligned. The commutation alignment recording is not correct until the toggle position and direction of toggle are clearly labeled.
3. For resolvers, enter the number of motor poles and resolver speeds in the drop-down lists to generate an Electrical Angle for recording alignment. If you choose to record the Resolver angle instead, remember that you need to record the entire set of +U-V and +U-W lockup angles at every motor pole pair.   

Get more accuracy from your lockups by using this technique: with the motor locked, torque the shaft in one direction, let it spring back, and record the angle. Then torque the motor in the other direction, let it spring back, and record the angle. Add these two angles together and divide by two for a more accurate lockup angle. If the motor is extremely large, you may need more current for a precise lockup than then Instek DC power supply can provide (10A max), and this averaging technique can help greatly. 

The feedback alignment should now be properly documented at this point, and is safe to begin dismantling the motor for repair. Sometimes the feedback nameplate is only visible after the feedback has been removed. The wire colors also may only be visible after breaking down the motor. Make sure to document any of these missing details on your datasheet whenever you find it. 

Video Reference: "TI-5000JX Document the Feedback Alignment"

9. Configure the TI-3000JX then Debug and Run the Motor

1. Choose the correct software module by pressing “SELECT MFR/FBK” button and using the arrow keys to navigate the various motor and feedback combinations. Enter all pertinent setup details using the “SETUP MOTOR/FBK” menu. Depending on the selection, there may or may not be any setup details to enter. The “Generic” licenses typically have the most setup details to enter, as shown below:
   1. (P) Number of motor poles.
   2. (C) Counts/rev for encoders, or (S) speeds for resolvers.
   3. (D) Direction.  Select either (S) same or (O) opposite depending on the relationship of the motor and feedback forward directions.
   4. (U) Unit. (Generic Resolver only).  Select either (E) electrical angles or (R) resolver angles, depending on which type was recorded on the 5000JX. See step 8.3 for more details.     
   5. (A) +U-V lockup angle.
   6. The Generic Resolver option you will have two extra setup screens; one to set the excitation voltage, and another to set the excitation frequency. You should be entering the same values that were found in step 6.2.2 above. The TI-3000JX will not run if the resolver vector level is below 2.0V or above 3.0V.
2. Debug the motor first before running.
   1. Press the “TEST” button and then enter “DEBUG” mode. Make sure the UVW commutation signals are toggling as the feedback is rotated.
                                                                                     U        V       W
   2. Lock the motor with +U-V and look for:           H/L     H      L
   3. Lock the motor with –W+U and look for:          L         H      L/H
      
      
3. If debug was successful as described above, run the motor in both directions. Turning the potentiometer CW from 0 position will move the motor in the forward direction. Make sure your motor is turning the correct forward direction as found in step 4. Turning the potentiometer CCW from 0 will move the motor in the reverse direction. The maximum speed the motor will run can be determined in step 5 above. A major speed imbalance in either direction might suggest an alignment setting issue, which should have been detected in debug.  

1. 1. 1. Press the “RUN” key, adhere to warnings, and press “RUN” again to enable the drive.
      2. Run the motor in the forward and reverse directions by turning the potentiometer. Make sure not to exceed the rated max RPMs of the motor.
      3. Return the potentiometer to the 0 position and press the STOP key.

Video Reference: "TI-3000JX Resolver Setup and Debug"

Reference for location of guide steps