S11/16 Series Switching Amplifiers

These amplifiers are intended for large systems. They are based on a half bridge, FET switcher PWB. The OUT-11 is rated at 1,000 VA. The OUT-16 is a higher powered PWB with more FETs which are rated at higher voltage and is rated at 2,500 VA. The OUT-16 design has just been finalized, but the circuitry and parts stress is virtually the same as the OUT-11. Due to the lower parts count, reduced wiring, and higher power density, the S16 is more compact and less expensive per watt than an equivalent S11.

Instruments, Inc. has delivered over 12,000 OUT-11 PWBs since 1987. The reliability of the OUT-11 has been very good. Actual experience has proved greater than a 290,000 hour MTBF per Output PWB.

A pair of boards forms a full bridge. Fast rectifiers and drivers are used for maximum efficiency. Full modulation control is allowed. The transistors are fully protected against load faults, excessive switching frequency, cooling failure, and start-up or power-down transients.

The various models of amplifiers are designated S11-xxm or S16-xxm where xx is the number of output boards and m is an optional modifier for special applications. These amplifiers are complete, having a suitable power supply, input preamp and an output filter/transformer system.

Amplifier

Models smaller than the S11-8 are rack mounting, therefore the size and weight is for the amplifier only. The models S11-8 and larger are delivered in a structure (rack), therefore their size and weight is the total and includes the "rack". Multiple cabinets may be designed into a system. The outputs are usually combined in series, since they are voltage sources.

The output transformers in models S11-2 through S11-24 are mounted from the front. These transformers may be designed for operation down to 50 Hz, however this reduces the high frequency performance and increases the weight slightly. In addition, models smaller than the S11-32 may be designed as specials to pass through a submarine hatch. The larger models have rear mounted transformers which operate down to 200 Hz and are not designed for submarine use.

Interface

The Interface function is accomplished with an analog Pre-Amp, analog output voltage and current monitors, and digital Fault Detection and Fault Location information. If needed, a summing transformer is included for load matching and/or high voltage output.

Power Supply

In our switching amplifiers, reactive currents are returned to the power supply. Thus, when driving a load with a power factor of 0, either capacitive or inductive, the power drawn from the primary AC source is only 15% of the output VA. Any real power delivered to the load increases the primary AC power. With a resistive load, at full power, the overall efficiency is about 75%.

OUT-11 1 kW Half Bridge Switching PWB.

(Click image to enlarge)

Specifications for Standard S11/16 Series Amplifiers

Type of amplifier	Full bridge equivalent, FET output, Switching
Modulation	Squarewave, Stair-Step, or PWM
Load power factor range	0 - 100% capacitive or inductive
Distortion (THD)	PWM: 2% max, 0.2% typical.
Frequency range (-3 dB)	PWM: STD	200 Hz to 20 kHz
		or 500 Hz to 40 kHz
	PMW: LF	50 Hz to 5 kHz
	Stair-Step: max sw freq	160 kHz
RMS noise	-60 dB gated on (PWM only)
(below max output)	-120 dB gated off
Current monitor	100 mV/A
Voltage monitor	2 mV/V
Protection	No combination of passive loads, input signals or
	switch settings will cause amplifier failure.
Fault lights	Temp limit, voltage limit, current limit, blown fuse
Ambient temperature	0 - 40 degrees C
Primary power (standard)	S11-2, 4	208/240 V 60 Hz 1ph
Contact factory for	S11-8 - 24	208/240 V 60 Hz 3ph
other AC voltages	S11-32 - 64	480 V 60 Hz 3ph
	S16-ALL	480 V 60 Hz 3ph

Individual Specifications

Model designation	S11-2	S11-4	S11-8	S11-16	S11-24	S11-32	S11-40
Output watts - continuous	1,000	2,000	4,000	8,000	12,000	16,000	20,000
- 100 sec burst @ 20%	2,000	4,000	8,000	16,000	24,000	32,000	40,000
Width (inches overall)	19	19	24.5	24.5	24.5	24.5	24.5
Depth (inches overall)	22	22	29.5	29.5	29.5	38	38
Height (inches overall)	14	22.75	49	62	75	57	63
Weight, std	140	200	600	1,200	1,400	1,600	1,800
Weight, low freq (pounds)	170	275	725	1,500	1,750
Amplifier Photograph	S11-2	S11-4	S11-8	S11-16	S11-24	S11-32	S11-40

Model designation	S11-48	S11-56	S11-64	S16-16	S16-24	S16-32B
Output watts - continuous	24,000	28,000	32,000	16,000	24,000	32,000
- 100 sec burst @ 20%	48,000	56,000	64,000	40,000	60,000	80,000
Width (inches overall)	24.5	24.5	24.5	28	28	28
Depth (inches overall)	38	38	38	45	45	30
Height (inches overall)	69	75	81	56	64	48
Weight (pounds)	2,000	2,200	2,400	1,800	2,200	600
Amplifier Photograph	S11-48	S11-56	S11-64	S16-16	S16-24	S16-32B

Models with an "A" have no cabinet, power supply, or output transformer.
Models with a "B" have no power supply.

Some models are available in a Multi Channel configuration.
Contact the factory for design limitations and cost.

For terms and foreign sales see PRICE POLICY in front of catalog.
Specifications and prices subject to change without notice.