Specifications are subject to change without notice.

Customers should verify actual device performance in their specific applications.

H-490 Turns-Counting Dial

Mechanical and Physical Characteristics

Number of Turns ..................................................................................................................................................................................0 to 30

Dial Divisions ...............................................................................................................................................................................100 per turn

Readability - Over 10 Turns ......................................................................................................................................................1 part in 1000

Torque With Brake Engaged .............................................................................................................................350 g-cm (5 oz-in.) minimum

Markings .............................................................................................................................................................White on black background

Locking Brake.................................................................................................................................................................Refer to chart below

Weight ..........................................................................................................................................................Approximately 7 grams (1/4 oz.)

Set Screws .............................................................................................................................................UNC-3A 4-40, 2 screws 120 º apart

Set Screw Tightening Torque ......................................................................................................................22.59 N-cm (2 lbs.-in.) minimum

Hex Key Size ................................................................................................................................................................................0.05 in. hex

Shaft and Bushing Requirements

Shaft Diameter Requirements ........................................................................................................................................Refer to chart below

Shaft Extension Beyond Panel .........................................................................................................................15.75 mm (0.62 in.) minimum

21.21 mm (0.83 in.) maximum

Bushing Extension Beyond Panel .....................................................................................................................9.02 mm (0.35 in.) maximum

0

9

1

2

25.4

(1.0)

45 ° ± 10 °

BRAKE

18.29

(.720)

12.7

(.500)

11.18

(.440)

23.11 ± .76

(.909 ± .029)

30 ° ± 5 °

RAD. MAX.

DIA.

10.36

(.407)

DIA.

Part

Accepts Shaft

Number

Diameter

Fits Bushing Size

Brake

Body Finish

H-493-2

3.18 mm (.125 in.)

6.35 mm-32UNEF-2A

No

Black

H-494-2

3.18 mm (.125 in.)

6.35 mm-32UNEF-2A

Yes

Black

H-491-3

6.35 mm (.250 in.)

9.53 mm-32UNEF-2A

No

Satin Chrome

H-492-3

6.35 mm (.250 in.)

9.53 mm-32UNEF-2A

Yes

Satin Chrome

H-493-3

6.35 mm (.250 in.)

9.53 mm-32UNEF-2A

No

Black

H-494-3

6.35 mm (.250 in.)

9.53 mm-32UNEF-2A

Yes

Black

H-492-2

3.18 mm (.125 in.)

6.35 mm-32UNEF-2A

Yes

Satin Chrome

H-490 MOUNTING INSTRUCTIONS

1. Discard standard mounting nut and lockwasher supplied with the

potentiometer; they will not be used.

2. Insert potentiometer in panel.

3. Using parts supplied with dial, position anti-rotation washer

against panel. Tangs of washer should stick out from panel.

4. Install mounting nut supplied with dial. Be sure:

a. Shoulder on nut engages hold of anti rotation washer.

b. Tangs of anti-rotation washer are aligned vertically.

This positions the turns-counting window properly.

5. Turn potentiometer shaft counterclockwise to minimum resistance

or voltage ratio. This is not necessarily at the end of travel.

6. Loosen set screw in knob of dial assembly. Set dial to “0.00”

reading. Slip dial assembly over end of potentiometer shaft.

7. Holding outer ring of dial assembly, engage locating tangs on

anti-rotation washer in notches on dial assembly.

8. While holding outer ring, position unit lightly against panel.

Uniformly tighten knob set screws to potentiometer shaft with

furnished hex wrench.

Dimensional Drawings

Features

■

No backlash - mounted directly to

potentiometer shaft

■

For use with precision potentiometers or

other rotating devices up to 30 turns

■

Compact size - requires only 25.4 mm

diameter panel space

■

Available with or without brake

DIMENSIONS:

MM

(INCHES)

How to Order

REV. 02/06

Model H-490 is currently available,

although not recommended for new

designs. Models H-23 and H-506 are

preferred.