Emoteq (Hathaway) BH02300E06HE BH series NEMA23 Servo Motor


The BH02300E06HE is a single stack 4 pole NEMA23 high speed brushless DC servo motor with a custom E winding and a US Digital E3-1000-250-I encoder. The original manfacturer was Hathaway, which has since become the Emoteq division of Allied Motion Technologies. It looks like Allied Motion doesn't want to acknowledge the BH series, but the datasheet is still available from them here (it took a bit of googling to find it).

The E3 encoder is a 1000 line (4000 count/rev) incremental optical encoder for a 0.25" shaft with index pulse. The standard E3 encoder has single ended outputs; however, the one on the BH02300E06HE has a differential line driver with flying leads. It is not a standard US Digital line driver (PC4 or PC5), since those have a 10 position pin header instead of flying leads.

I was able to verify the location of the A+,A-,B+,and B- signals, but I am not positive I have the I+ and I- phases correct..

One of my two BH02300 motors does not have the index signals (I+, I-) connected, and does not appear to output the index pulse, even if you connect wires to the empty positions.

I highly recommend having some strain relief near the encoder - the connections can be very brittle and break easily, and it's not easy to re-solder the wires. It would have been much nicer if Hathaway had used a PC4 line driver.

The single stack BH02300 is very fast (its torque curve starts at 20000 RPM, and I've run mine at 21000 RPM at 150V) with relatively low continuous torque (14.3 oz-in) and a high maximum to continuous torque ratio (161:14.3, which is 11:1; most servo motors have a 3:1 ratio). The longer BH0230x versions with more torque, such as the double stack BH02301, are significantly slower.

Notes on Encoders and High Speed Operation

Most encoders are rated for a high mechanical speed, but lower electrical/optical speed (maximum number of cycles (optical lines) per second). For example, the US Digital E3 is rated at 60,000 RPM mechanical, and 100,000 cycles per second, while the CUI AMT102 is rated at 15,000 RPM mechanical and 250,000 cycles per second. Note: I recall seeing 30,000 RPM for the AMT102, but the current specifications show 15,000 RPM for max speed.

So a 1000-line/4000-count E3 is rated at 6000 RPM. That's probably pretty conservative, since I didn't notice problems at 21,000 RPM -- except it appears my optical encoder disk got too hot and deformed. My guess is that for some reason it was rubbing against one side of the encoder read head.

I could replace the disk (since US Digital sells the disk only), but I'm considering replacing it with a CUI AMT102, since they're affordable and I can set the resolution via DIP switch. Then I can set the AMT102 to high resolution (8192 counts/rev) for lower speeds, and low resolution (2048 counts/rev) for high speed.


Since I do not have the specifications for this winding ("E"), I do not know the motor's electrical specifications. It looks like the "E" winding is between the "B" (43V) and "C" (130V) windings. My guess is that the "E" winding has a design voltage of ~75V, and a Kb (V/kRPM) of ~7 since I reached about 7500 RPM with a 52V power supply and about 21000 RPM with a 150V power supply.

Mechanical Specifications

Max Cont Stall Torque14.3oz-in
Max Rated Torque, 25%161oz-in
Max Cont Output Power113W
Max Cogging Torque1.56oz-in
Motor Inertia8.3E-4oz-in-sec-sec

Winding Constants

For E winding, unknown. I measured the Terminal Resistance at about 4 Ohms, and the Kb is about 7 V/Krpm. I am listing the B and C windings below:

Parameter BCUnit
Design VoltageVp43130V
Peak TorqueTp106133oz-in
Peak CurrentIp19.39.6A
Torque ConstantKt5.5413.85oz-in/A
No Load SpeedSnl1041012600RPM
BEMF ConstantKb4.0910.24V/KRPM
Terminal ResistanceRm2.2313.5Ohm
Terminal InductanceLm0.714.42mH

Motor Connections


The motor power wires are the red, white, and black wires coming from the motor's body.

PhaseWire Color

Hall Sensor

The motor has three hall sensors built into its body.

PhaseWire Color


The motor encoder outputs are the eight flying leads coming from the encoder (six on one of my motors - it has no index signal). In general, without documentation it is impossible to tell which signal is the positive signal and which signal is the negative signal; however I was able to verify the A+/A- and B+/B- signals. Switching the A+ and A- signals reverses the encoder direction.

My standard is positive is when the motor, when viewed from the front, is turning clockwise.

SignalWire Color
+5VDC Blue
A+ Red
A- Brown
B+ Orange
B- Yellow

Connections to Specific Drives and Amplifiers

Copley Accelnet Panel ACP series


The Accelnet's motor outputs are on the J1 connector (6 position removable screw terminal block).

Motor NameMotor ColorCopley ConnectorCopley PinCopley Name
Phase CBlackJ11Motor U Output
Phase BWhiteJ12Motor V Output
Phase ARed J13Motor W Output

Hall Sensor

The Accelnet's hall sensor inputs are on the J2 Feedback connector. The Copley wire colors are for a Copley ACP-FC-10 Feedback Cable.

Motor SignalMotor ColorCopley ConnectorCopley PinCopley ColorCopley Signal
Hall +5VBlue J23 Brown/White+5 VDC
Hall GNDGreen J210White/GreenSignal Ground
Hall 3 YellowJ211Tan/White Digital Hall U
Hall 2 OrangeJ212White/Blue Digital Hall V
Hall 1 Brown J213Blue/White Digital Hall W


The Copley wire colors are for a Copley ACP-FC-10 Feedback Cable.

Motor SignalMotor ColorCopley ConnectorCopley PinCopley ColorCopley Signal
GroundGreen J22White/Brown Signal Ground
+5VDC Blue J23Brown/White +5VDC
A+ Red J24White/Pink Encoder A Input
A- Brown J25Pink/White Encoder /A Input
B+ OrangeJ26White/OrangeEncoder B Input
B- YellowJ27Orange/WhiteEncoder /B Input
Index+Black J28White/YellowEncoder X Input
Index-White J29Yellow/WhiteEncoder /X Input

Motor Setup

The Copley Accelnet drives accept almost any cable configuration, since they will auto-phase to figure out the correct motor phase, hall phase, and encoder phase sequence. However, my connections below minimize any changes; in other words, the motor phasing is not inverted, the encoder is not inverted, and the hall sensor order is UVW. My connections are done so positive motion is the shaft turning clockwise when facing the motor.

Since I do not have the specifications for this winding ("E"), I do not know the motor specifications (which can be entered in the Motor tab of the Motor/Feedback dialog). Instead, I let CME2 autotune the current loop. The autotuning produced a reasonable starting point.

Last modified 4 years ago Last modified on Jun 20, 2013 9:11:26 PM