Wilcoxon Research PA8HF Operating Manual Download Page 5

 

 

 

 

 

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1.0  Product description

 

 
The PA8HF is a single-channel, rack-mountable power amplifier designed to high performance 
standards.  The PA8HF develops a maximum of 800 watts of power into a 4 Ohm load. The 
amplifier will drive the full range of Wilcoxon Research shakers, with the ability to drive the larger 
shakers to the full performance limits of the shakers. 
 
The PA8HF combines the latest power amplifier technology with uniquely simple circuit 
technology to reduce distortion of all types, and at all power levels, over the full frequency range. 
In addition to performance achievements, the power amplifier is designed for long-term reliability 
and exceptional resistance to abusive operating conditions. 
 
The power amplifier has circuit breaker protection for AC power input and fuse protection for the 
output of the power amplifier. 
 
Specifications   

 

PA8HF 

Power output   

 

800 Watts, maximum, into 4

 load    

Power bandwidth 

 

0.5 Hz to 100,000 Hz  

Output fusing   

 

12 Ampere, type 3AG or AGC, fast-blow  

Input sensitivity 

 

2.5 Volt peak, for full output  

Input impedance 

 

50 k

, nominal 

Dimensions 

 

 

19” wide, 17.5” deep, 5.25” high 

Weight 

 

 

50 lb 

Power requirements   

2,000 Watts, maximum 

 

1.1 Front panel 

 

1.1.1  Power switch:

 The power switch is located on the lower center of the front panel and 

serves to energize the power amplifier from the AC power line. The switch is a membrane type 
and latches the power when depressed to place the power in the “ON” or the “OFF” condition. 
 

1.1.2  Power indicator:

 The PA8HF has an LED indicator above the power switch to monitor the 

following conditions: 

  Unlit - indicates the amplifier has no power. 
  Red - indicates the amplifier is muted (power-up) 
  Green - indicates the amplifier operation is normal. 
  Flashing red - indicates the amplifier clipping. 
  Orange - indicates channel thermal shutdown. 

 

1.1.3  Output fuse:

 One output power amplifier fuse is located in the upper right corner of the 

front panel. This fuse is connected in the power amplifier output circuit to aid in protecting the 
power amplifier or shaker from excessive current. The PA8HF power amplifier is supplied with a 
12 Ampere fuse. The recommended fuse type is 3AG or AGC. Manual section 2.1 lists other 
values of fuses that may be used when driving electromagnetic shakers.  
 

CAUTION:  

To prevent damage to equipment, NEVER replace a fuse with anything 

other than the type and value specified.  Using values other than those specified will 
void the equipment warranty and may cause fire or injury to personnel. 

 

Summary of Contents for PA8HF

Page 1: ... Germantown MD 20876 USA Meggitt Maryland Inc d b a Meggitt Sensing Systems Tel 1 301 330 8811 Tel 1 800 WILCOXON Fax 1 301 330 8873 www meggittsensingsystems com www meggitt com 97012 Rev C 1 4 13 Wilcoxon Research PA8HF power amplifier Operating guide ...

Page 2: ...electromagnetic shaker 7 2 2 Using the power amplifier with a piezoelectric shaker 7 2 3 Matching networks 8 3 0 Initial system setup 9 3 1 AC line power 9 3 2 Signal input 9 3 3 The power amplifier matching network and shaker cables 9 4 0 Operation 10 4 1 Applying power 10 4 2 Test operation 10 5 0 Maintenance 11 6 0 Technical assistance 12 6 1 Technical assistance 12 6 2 Customer service 12 ...

Page 3: ...HE AMPLIFIER ENCLOSURE Safety section The power amplifier can be safely operated when the instructions in this manual are carefully followed This section summarizes the safety considerations Reminders in the form described below will appear in the detailed instructions to assure operator awareness of these safety considerations Qualified personnel should operate and maintain this power amplifier o...

Page 4: ...wer is connected Inspect for frayed or cut cables prior to operation 7 Hearing protection devices are highly recommended in the vicinity of a piezoelectric shaker whenever the shaker is being driven at high output levels 8 Do not expose this equipment to rain or moisture 9 Lethal high voltage may be present at the power amplifier output connector 10 When using the D125L piezoelectric shaker it req...

Page 5: ...quirements 2 000 Watts maximum 1 1 Front panel 1 1 1 Power switch The power switch is located on the lower center of the front panel and serves to energize the power amplifier from the AC power line The switch is a membrane type and latches the power when depressed to place the power in the ON or the OFF condition 1 1 2 Power indicator The PA8HF has an LED indicator above the power switch to monit...

Page 6: ... set to the OUT position when driving electromagnetic shakers such as the F3 F4 F5B or the F10 Check the position of this switch if you have low output from your electromagnetic shaker 1 2 6 Auto local switch In local position either the front panel power switch or an external voltage controls the power up of the amplifier Auto is used when the amplifier is powered from a switched power outlet The...

Page 7: ...orks attached to the output of the amplifier Users may wish to replace the 12 Amp fuse shipped with the amplifier with a smaller value to insure excessive current is not applied to the electrodynamic shakers Use AGC or 3AG type fuses The maximum safe current to each shaker is as follows Model Current F5B 0 1 Amp F3 0 75 Amp F4 1 5 Amp no cooling unit 2 5 Amp with cooling unit F10 4 Amp 2 2 Using t...

Page 8: ...the matching network s transformer the voltage at the piezoelectric shaker rolls off at 20dB per decade after the corner frequency exactly like an RC filter As the voltage switch setting on the matching network is switched from highest to lowest setting the bandwidth of the system will increase In general piezoshakers can be operated at their lower frequencies with the matching network switch in i...

Page 9: ...al amplitude is controlled by the signal generator amplitude control It is recommended that the signal generating amplitude control be preset considering the signal generator s capability to eliminate the possibility of overdriving the power amplifier 3 3 The power amplifier matching network and shaker cables Electromagnetic shakers do not require a matching network and are connected directly to t...

Page 10: ...cates a more powerful amplifier is needed for that application The PA8HF has thermal shutdown circuitry to prevent damage due to overheating Should thermal shutdown occur the amplifier will mute and the LED will turn orange indicating this condition When the amplifier has cooled to a safe operating condition the PA8HF will return to normal operation Persistent thermal shutdown indicates a cooling ...

Page 11: ...e warranty and may cause fire or injury to personnel The output fuse located on the front panel should only be replaced with AGC or 3AG types as supplied with your system When removing this fuse ensure that power is not applied to the power amplifier The output fuse because of its construction may interrupt the circuit before a circuit breaker on a matching network opens DO NOT substitute a higher...

Page 12: ...or technical assistance please contact Meggitt Sensing Systems customer service at 301 330 8811 or email techasst meggitt com 6 2 Customer service To obtain a return materials authorization number please contact customer service at 301 330 8811 or fax to 301 330 8873 ...

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