10

Automatic Timing & Controls

800.727.5646

atcdiversified.com

Percentage Timer

MODELS

304E plug-in

Choice of three:

304E non-plug-in

304C non-plug-in

RANGES

15 SEC @ 60 cycles (18 SEC @ 50 cycles)

Choice of three

30 SEC @ 60 cycles (36 SEC @ 50 cycles)

standard ranges.

60 SEC @ 60 cycles (72 SEC @ 50 cycles)

REPEAT ACCURACY

± 0.1%

DIAL CALIBRATION

5 to 95% on time, in 1% graduations.

FULL ON, FULL OFF FEATURE. When

pointer is set below 3%, load switch

contacts are open continuously, above

98%,contacts are closed continuously.

LOAD SWITCH

One SPST(quick make, quick break)

switch with self-cleaning heavy-duty

silver contacts.

CONTACT RATINGS

304C

25A at 120 VAC

20A at 240 VAC

304E

15A at 120 or 10A at

240 VAC plug-in unit.

Non-plug-in unit same as 304C

POWER REQUIREMENTS 120 or 240V, 50/60 Hz; 50 mA

running current.

TERMINALS

4 screw terminals accessible at rear;

wiring diagram on housing.

TEMPERATURE RATING 32° to 120°F (0°to 50°C)

WEIGHT

NET: 1 lb., 2 oz. SHIPPING: 1 lb., 7 oz.

SPECIFICATIONS

OPERATION

Easily the most rugged and dependable of industrial percentage

timers, the ATC 304 incorporates heavy-duty contacts that are capable

of switching loads as large as 4.6 KW directly.

LARGE CONTACTS: Self-cleaning silver contacts are 3/8 inch in

diameter, larger than in any other make of percentage timer. They

easily provide 1,000,000 operations at the full rated load of 25 A

(non plug-in models).

RUGGED AND TROUBLE-FREE: Every component of the 304 has been

refined and improved over the years to provide dependable operation

for at least 3,000,000 cycles. Its classic simplicity of design makes it

virtually trouble-free.

CONVENIENT ADJUSTMENT: Graduated in easily read 1% increments,

the 304 provides continuous adjustment of on time between 5 and

95%. It also switches the load off continuously when the pointer is set

below 3%; and on continuously, when the pointer is set above 98%.

The 304 is available in a choice of 15, 30 and 60-second time

cycles (60 Hz). Its synchronous motor drives a cam which repeat-

edly closes the SPST load switch for a percentage of the time

cycle, as set on the timer dial, and opens it for the remainder of

the cycle.

When the dial pointer is set below 3%, the load switch stays open

for the full cycle; it remains closed when the pointer is set above

98%. An optional Hold switch also disconnects power to the timer

motor when the pointer is set below 3%.

Series 304 timers operate continuously and do not reset on

power interruption; when power is restored, they resume the

interrupted cycle.

TYPICAL APPLICATIONS: Ideal for controlling wattage input to

electrically heated equipment, the 304 non-plug-in models can

pulse loads up to 4.6 KW directly through the SPST load switch;

the plug-in models can switch up to 2.3 KW loads directly.

The 304 can be used with other types of electrical equipment to

control the ratio of on time and off time in a fixed time cycle. In

many types of ratio and cascade control systems, the 304

provides rate-of-rise set point drive control; special dial

calibrations are available for this application.

E24305

Automatic Timing & Controls

800.727.5646

atcdiversified.com