Application Note AN-244
The MB500VI
Power Amplifier
for Remote Setup, Operation, and Monitoring
PURPOSE
shevaThe purpo of this Application Note is to provide all information necessary to u operate the MB Model 500VI Power Amplifier in systems where the amplifier is to be operated with MB’s Remote Setup, Operation and Moni-toring package, including the Remote PC Ur Interface software (e AN-210, latest revision level).
The need for “periodic adjustment” is minimized by the design of the unit. Although there are internal potenti-ometers, the devices should not be adjusted without proper test equipment or procedures, procedures which are not part of this Application Note. Should repairs or adjustments be required, plea contact MB Dynamics Customer Service personnel, who may either provide the necessary information or may request that the unit be returned to factory for evaluation and repair.
INTRODUCTION
The MB500VI is a Linear Power Amplifier designed to operate in conjunction with MB’s line of voice
coil electro-dynamic vibration exciters. It is totally air cooled and compatible with most power systems throughout the world. The amplifier includes both temperature and current protection devices, as well as a convenient ur interface which provides information about the amplifier’s operation, including voltage and current being delivered to the attached load.
Front and Rear Panel Views
MB500VI Power Amplifier
Author: William Run, MB Dynamics
The amplifier also provides for two very different operat-ing modes:
1) VOLTAGE MODE – In this mode (the “V” mode),
the amplifier is configured to output a voltage which is proportional to the commanded voltage at the unit’s input. The output impedance of the amplifier in Voltage Mode is very low, typically less than 0.1 ohms, and the amount of current
delivered to the load will be varied to maintain the load voltage at the commanded level.
2) CURRENT MODE – In this mode (the “I” mode), the amplifier is configured to output a current which is
proportional to the commanded voltage at the unit’s input. The output impedance of the amplifier in Current Mode is very high, typically greater than 500 ohms, and the amount of voltage delivered to the load will be varied to maintain the load current at the commanded level.
Voltage mode is the typical mode of operation for most standard vibration testing – durability, squeak and rattle evaluations, etc. Current mode is often the mode ud for modal testing. The amplifier bandwidth is reduced in current mode such that operation above 2000 - 3000 Hz is compromid.
The amplifier comes prepackaged in a 3.5” high chassis, suitable for mounting into a 19” rack if desired, or for placement onto a benchtop.
SPECIFICATIONS
OUTPUT VOLTAGE
The MB500VI permits the ur to scale the full-scale input to produce full output voltage. Within the unit, a jumper (J8) “programs” the unit for the appropriate full scale input. Valid ranges are 1Vpk, 3Vpk, 5Vpk, and 10Vpk for full output. Full scale output voltage is 25V RMS Sine (35V PK ).
FREQUENCY RESPONSE
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SLEW RATE
untetherTypically 4V/uc
HARMONIC DISTORTION
0.5% at 100Hz and 10V rms into 4 ohm load
DC ADJUST
Ur adjustable via front panel recesd potentiometer which adjusts the DC voltage out of the power amplifier stage. Requires screwdriver adjustment. Adjust range from -1.5 to +1.5VDC at the output in Voltage Mode.
VOLTAGE MODE GAIN (“V” Mode)硬干
Approximately 30 at MAX tting on the front panel GAIN control and for a programmed input maxi-mum level of 1Vpk. Gain is approximately 10 for 3Vpk programmed input.
CURRENT MODE GAIN (“I” Mode)
Approximately 28A/V at MAX tting on the front panel GAIN control and for a programmed input max-imum level of 1Vpk. Gain is approximately 10A/V for 3Vpk programmed input.
FRONT PANEL CONTROLS
Gain – A two position center off toggle switch that permits operator gain control from 0 to 100% of full scale in 1% increments. While being adjusted, gain is displayed on the LCD display. By holding the GAIN switch in either the UP or DN directions, the gain adjustment range switches from 1% increments to 10% increments, to facilitate rapid movement to a desired gain tting. Once “in rang
e” for the de-sired gain, the switch may be CLICKED (quick transitions from center off to either UP or DN) to incre-ment or decrement the gain in 1% increments. When gain is adjusted from the remote software GUI, an operator may enter a desired gain for the amplifier over the Ethernet connected system (PC to MB500VI).
NOTE: WHILE GAIN IS BEING ADJUSTED, THE OUTPUT OF THE AMPLIFIER IS DISABLED AND THE SIGNAL PATH COMPRESSED. AFTER GAIN IS SET TO THE DESIRED LEVEL, THERE IS A DELAY TIME TO RE-ENABLE THE AMPLIFIER OF APPROXIMATELY 10 SECONDS BEFORE POWER WILL BE PRODUCED AT THE AMPLIFIER OUTPUT TERMINALS.
DISABLE – This is a large RED pushbutton switch that can be ud to EITHER; a) cau the output of the MB500VI to go immediately to ZERO (output OPEN), or; b) RESET a FAULT in any displayed fault condition before resuming operation.
INPUT – A pair of BNC’s which provide the command input signal to the amplifier. Factory tting scales this input so that 3Vpk into the input caus full scale output at the connected load in Voltage (“V”) mode and into a load of 4 ohms or greater. The BNC labeled “DC” operates over the bandwidth shown in the “Input Gain” graph shown on Page 2 above. The BNC labeled “AC” caus
the low fre-quency performance of the amplifier to be down -3dB at approximately 20Hz, to more cloly approxi-mate the performance of a “standard” audio amplifier. For vibration testing, the “DC” input should be ud.
V/I Mode – A center off momentary switch which ts the amplifier to either the voltage (“V”) or the current (“I”) operating mode, with the lected mode shown on the LCD display. The switch is inter-locked with the ENABLE condition of the amplifier, and only permits the operating mode of the amplifier to be changed when in the DISABLED (after a push of the DISABLE button) condition. The mode -lected and which is active is shown by causing the CLIP/TRIP LED for that mode (“V” or “I”) to glow GREEN, with the opposite mode’s CLIP/TRIP LED being in the OFF state.
V Monitor – A BNC which provides an output signal that is proportional to the output voltage of the am-plifier, with the signal nsitivity being 4V/V (i.e. 250mV out of this BNC equals 1V out of the amplifier).
I Monitor – A BNC which provides an output signal that is proportional to the output current of the am-plifier, with the signal nsitivity being 4A/V (i.e. 250mV out of this BNC equals 1A out of the amplifier).
DC ADJ – A recesd potentiometer which provides a means for the operator to change the DC output of the amplifier, a convenient way to “re-center” a vibration exciter which may not be quite at the cen-ter of its stroke.
riskyV Clip – A tri-color LED which glows GREEN to indicate the operating mode lected for the amplifier (“V” or Voltage mode), and which flashes RED to indicate that a Voltage Clip is occurring, and then glows YELLOW to show that a clip has occurred. The amplifier hardware can be configured to cau it to FAULT (which caus the output to OPEN and the exciter to STOP being driven), or only to display that a voltage has been produced by the amplifier that is greater than the programmed CLIP voltage but not to FAULT as a result of the higher voltage. If tup to FAULT, the operator must press the DISABLE switch to ret the system. See “J7” under “Jumper Settings” below.
I Clip – A tri-color LED which glows GREEN to indicate the operating mode lected for the amplifier (“I” or Current mode), and which flashes RED to indicate that a Current Clip is occurring, and then glows YELLOW to show that a clip has occurred. The amplifier hardware can be configured to cau it to FAULT (which caus the output to OPEN and the exciter to STOP being driven), or only to display that a current has been produced by the amplifier that is greater than the programmed CLIP alonzo
current but not to FAULT as a result of the higher current. If tup to FAULT, the operator must press the DISABLE switch to ret the system. See “J7” under “Jumper Settings” below.
Clip/Trip Adjust – This two position/center off switch permits the ur to adjust the maximum desired voltage or current the MB500VI will deliver to the connected load. Adjustment can only be done in the RESET state (after pressing DISABLE). When the MODE switch lects the VOLT mode, this control permits the maximum output voltage to be adjusted. When the MODE switch lects the CURRENT mode, this control permits the maximum output current to be adjusted. Adjustment is in integer values from a minimum of 5 for either VOLTS or AMPS to the maximum, which is 28V RMS for voltage and
25A RMS for current. The value entered is stored in memory within the MB500VI, and does NOT require re-programming at each successive power-up of the unit.
Table 1 below lists the various MB Vibration Exciters which are most commonly paired with the MB500VI, and the MB recommended voltage and current trip ttings for each. Plea note, the rec-ommended ttings are for exciters run to FULL performance, that is, with exciter cooling ON, and also for exciters run without cooling, which MB normally recommends at one-half of full rated for
ce. Your tting will depend upon the cooling configuration to be ud. Also plea note that the current trip points are most important to protecting a connected exciter from damage due to overdriven conditions. If the operator wishes to pair the MB500VI with a non-MB vibration exciter, we recommend that you contact MB Customer Service at 216-292-5850 X111 for assistance in determining appropriate trip points for the intended exciter.
Exciter, with cooling
condition
Volts RMS
Standard
我的自白九年级上册英语单词10m Cable
Volts RMS
Optional
30m Cable
Volts RMS
Optional
40m Cable
Volts RMS
Optional
45m Cable
Amps RMS
All Drive
Cables
PM25 cooled 18 18 18 18 10
PM25 uncooled 12 17 20 23 5
CAL25HF 28 N/A N/A N/A 15
MODAL 25 cooled 18 24 26 28 10
MODAL 25 uncooled 12 17 20 23 5
PM50 cooled 28 28 28 28 10
PM50 uncooled 16 23 26 28 5
MODAL 50 cooled 28 28 28 28 10
MODAL 50 uncooled 16 23 26 28 5
CAL 50 cooled 28 28 28 28 10
CAL 50 uncooled 16 23 26 28 5
motion是什么意思
PM100 cooled 28 28 28 28 18
PM100 uncooled 16 23 26 28 9
MODAL 110 cooled 28 28 28 28 28
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MODAL 110 uncooled 16 23 26 28 14 ENERGIZER RED cooled 28 28 28 28 28 ENERGIZER RED uncooled 16 23 26 28 14
Table 1
Recommended V/I Trip Settings
for MB Vibration Exciters
The data in Table 1 are taken at a frequency of 100Hz. However, in some modal exciter applications, the MB500VI may be located a long distance away from the driven exciter. When this occurs, the in-ductance of the drive cable also has an effect in the voltage drop en at the shaker load. The graph shown below provides expected voltage drop data for such Modal applications bad on cable length. The graph is prented for a driven current from the amplifier of 20Arms. For currents less than this, the graph can be scaled by the ratio of i RMS/20.
IMPORTANT NOTE
WHEN DRIVING SHAKERS WITH LONG DRIVE CABLES, IT IS ESSENTIAL THAT THE CABLES BE STRETCHED TO FULL LENGTH, WITHOUT HAVING ANY “LOOPS” OR CROSSING OF THE
CABLE ONTO ITSELF. DOING SO INCREASES THE INDUCTANCE OF THE DRIVEN CABLE, AND CAN INDUCE MUCH HIGHER INDUCTIVE LOSSES IN THE DRIVE CABLE.
Main Display – This two-line, 16 character LCD display shows the status of the amplifier at any given time. When faults occur, it displays the faulted conditions, and if there is more than one fault, it dis-plays them quentially. When in the DISABLED mode, the unit is in standby waiting for commands, ei-ther to adjust the amplifier MODE or the CLIP/TRIP levels. When the Gain is UP (greater than zero), the display normally shows the amount of voltage and current delivered to the connected load. OUTPUT METERING
The metering circuits are bad on RMS to DC conversion of the output signals, and therefore reprent the RMS value of both voltage and current at the output of the MB500VI. The frequency linearity of the circuit is shown in the two charts below. Amplitude accuracy is specified at +5%. The specifications are no different from tho associated with standard hand-held meters, which also ‘roll-off’ the meas-ured signals at lower frequencies. It does not change the values that can be measured at the MONITOR output BNC’s, who values are not procesd by the RMS to DC converters, but only the physical numbers shown on the LCD display for AC voltage and current.
