Trimble EZ Steer motor specifications/information

Below are specifications and information about the Trimble EZ Steer motor.

Weight of assembly including mount/pivot: ~4478 gram

Connector: DB9, male pins
EZ Steer db9 pinout
Pin 1: Motor+
Pin 2: Motor+
Pin 3: Motor-
Pin 4: Motor-
Pin 5: Not Used
Pin 6: 5v Encoder Supply
Pin 7: Encoder Ground
Pin 8: Encoder Channel A
Pin 9: Encoder Channel B

Encoder is quadrature with 120 counts per revolution (each channel is 30 pulses per revolution). Channels are open collector output. I used 10k pullup resistors in my 5v breadboard test with an Arduino Micro. The encoder draws 14mA @5v. I have made an additional 3.3v breadboard test with a Teensy 4.1 using the internal pullup resistors. The encoder draws 10mA @ 3.3v.

Cable 18 awg, approximately 14" long.

Motor can diameter: 85 mm
Motor can length: ~135 mm
The motor has replaceable brushes.
The motor bottom has a sticker with number 53058-00 and a serial number. This number is the Trimble part number that is also on the sticker on the outside of the plastic shroud. There are no other motor markings or identifiers.
4x mounting screws, 10-32 thread
The motor windings measure to be 1.9 Ohm.

Foam wheel outside diameter: ~50mm
The foam wheel is marked with T.M. R.C. RACING COMPONENTS. This is a small American company that sells foam wheels for RC pan cars and RC drag cars. I have contacted this company before about replacements but they will only sell the wheel to Trimble directly.

All fasteners appear to be SAE. I would assume that this was designed in the USA.

Voltage, freewheel RPM, freewheel current, stall current
03.30v 179rpm 0.275a 1.651a
05.00v 286rpm 0.338a 2.490a
08.00v 480rpm 0.370a 4.032a
10.00v 610rpm 0.376a 5.437a
12.00v 740rpm 0.412a 6.679a
13.60v 844rpm 0.408a 7.520a

Foam wheel diameter

Under the plastic shroud

Replaceable motor brushes

Pulses in 10x motor revolutions

Reading the encoder with Arduino Pro Micro 5v

Motor windings resistance

How RPMs were measured

13.60v freewheel current

13.60v freewheel RPM

13.60v stall current

The other voltage/rpm/current measurement were taken in similar fashion.


Thank you for the detailed tech specs!

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Just doing some math.

The Phidgets 3269_2 motor/gearbox at 24v is 588 RPM, PotatoFarmer’s Universal Fit Gear System that is often used has a 5:1 reduction, for approximately 118 RPM at the steering wheel.

The EZ steer motor at 13.6v is 844 RPM, the 50mm foam wheel against a typical John Deere 15-3/4" (400mm) steering wheel is an 8:1 reduction, for approximately 106 RPM at the steering wheel.

I have often read that the EZ steer motor may be a too slow for U turns, but the calculations show the EZ steer is only ~10% slower than the phidgets.

Of course everything is slower than theoretical math due do RPM drop, foam wheel squish, foam wheel slippage.

I have been using the EZ steer motor with AOG AIO successfully for a season. I use it for U turns with a 20’ drill at 5.5mph, it won’t U turn much faster/tighter than that. Steering on not-straight boundaries doesn’t seem to be a problem. With the freewheel mod on the cytron and the current sensing on the AIO; the system behaves much the same as the original Trimble system did.

I don’t have a Phidgets motor to compare to. I do wonder if the additional gear reduction of the Phidgets motor leads to better controllability than the direct drive EZ steer motor.

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Will know the difference next spring have 2 EZ steer conversions to do.

The phidgets max speed is usually reduced to not over steer in AOG tuning anyway, rarely do you need max speed from it. The motor is very robust. The next slower rpm phidgets gearbox is extremely hard to steer during freewheel unfortunately.

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