Open Frame series  
Type A (Acorn)

1 inch diameter switches with Electroswitch patented Unidex® detent for positive action, feel and torque control. Double-wiping, self-cleaning contacts in silver plated brass, or silver alloy. Unique protective coating guards against tarnish and corrosion, extends shelf life.

Specifications
Size   1" diameter nominal, with 1 to 3 sections.
Max. depth, 1.281"
Mounting Clearance holes for a .375" -32 bushing and a .120"
diameter locating key on a .375" radius
Shaft .250" diameter (+.000 -.003); 1.50" long; grooved for
break-off at .75" and 1.125" from mounting surface
Indexing Unidex® dual ball, 30°
Terminal Strength 2.5 lb. pull
Stator Insulation Diallyl phthalate per MIL-M-14
Rotor Insulation Thermoplastic
Section Thickness .078"
Contacts Silver-plated brass or silver alloy. Protective coating
extends shelf life
Contact Resistance .003 to .015 ohms between adjacent clips
Electrical Rating Break .5 amp at 28 volts DC, .25 amp at 110 volts AC,
resistive. Carry 5 amps

Type A dimensions

Type A Switch Components

Basic Type A components provide the additional flexibility of meeting specific design requirements through distributor assembly of these components into other switch configurations.

Type A components
PC Hole Pattern

Type AM Switch Assemblies
With silver-plated brass contacts and solder terminals
Total Poles Active Positions Poles/Section Circuit Configuration Number of Sections Catalog Number
Shorting Non-Shorting
1 2-12 1 Fig. 1 1 399279-AM 399280-AM
2 2-6 2 Fig. 2 1 399281-AM 399282-AM
2 2-12 1 Fig. 1 2 399283-AM 399284-AM
3 2-5 3 Fig. 7 1 399260-AM 399261-AM
3 2-12 1 Fig. 1 3 399285-AM 399286-AM
Figure 1Figure 2Figure 7

Type A Rotary Section
AM rotary sections with silver-plated brass contacts and solder terminals
Total Poles Active Positions Section Type Circuit Configuration Catalog Number
Shorting Non-Shorting
1 2-12 Standard Fig. 1 399114-AM 399174-AM
2 2-6 Standard Fig. 2 399115-AM 399175-AM
3 2-5 Standard Fig. 7 399106-AM* 399107-AM
1 2-12 Notched Blade Fig. 9 399117-AM* ---
1 2-10 Consecutive Shorting Fig. 10 399118-AM* ---
1 --- Capacitor Decade Fig. 12 --- 399177-AM*
1 --- Resistor Decade Fig. 13 --- 399178-AM*
1 --- Binary Coded 0-11 Fig. 11 --- 399259-AM*
With printed circuit terminals
1 2-12 Standard PC Fig. 1 399136-AM* 399137-AM*
2 2-6 Standard PC Fig. 2 399138-AM* 399139-AM*
3 2-5 Standard PC Fig. 7 399156-AM* 399157-AM*
Type A 'PCB' sections with silver alloy printed circuit terminals, glass epoxy insulation
1 2-12 APBC Fig. 21 4-1432-755* 4-1442-140*
2 2-6 APBC Fig. 20 4-2552-115* 4-2552-415*

*Available made-to-order only.
Figure 9     Figure 10

Figure 11Figure 12

Figure 13

Figures 20 and 21

Shaft and Index Assemblies
Includes mounting nut and lockwasher, stopwasher, strut screws, assorted spacers, washers, and nuts.
Catalog Number Dimension "A"
(see above dimensioned drawing)
399257-A 1.375" (35.0 mm)
399258-A 4.875" (123.8 mm)