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MP 500 test bench for prime movers
(braking dynamometer) with MP Computer
In the following the basic design is described. A wide variety of standard functions is additionaly available.
In basic design the engine test bed is not supposed to be run unattended, if internal faults of the test bed or external faults may lead to dangerous situations.
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Loading system |
air-cooled electromagnetic eddy-current brake |
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periodically for very short time: |
6700 r.p.m. |
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The dynamometer consists of the braking and measuring unit and the control unit (evaluation, display and control unit with MP computer) contained in an operator's desk stand and connected to the braking and measuring unit by cables and plugs.
If a prime mover shall be tested, it is moved on its support towards the braking and measuring unit and the support is being fixed by one or two screws to the braking and measuring unit.
While moving the prime mover on its support to the braking and measuring unit, the prime mover is connected to the brake by sliding together the multiple-spline parts of the cardan shaft thus coupling the prime mover to the brake.
In case a tractor shall be tested by its PTO, an additional lateral support of the braking and measuring unit can be necessary.
If a prime mover is tested, the cardan shaft is positioned in a protective housing fixed to the braking and measuring unit. The brake is protected against accidental contact by means of a protective grating.
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Weights: |
braking and measuring unit |
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Space required |
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during operation: |
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approx. 1.8 m x 2.0 m |
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Space required by the operator's desk stand (standard): |
approx. 0.5 m x 1.0 m |
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Power supply: |
400 V 3-phase AC, 50/60 Hz Other supply voltages are possible. |
Control and measurement
The control unit contains:
- the MP Computer,
- the control circuitries for the eddy-current brake and
- the required supply devices.
Protection class of the control unit: IP 55
Rotational speed n, torque M, power P, work (energy) W
Loading the prime mover by the brake is manually controlled by an input potentiometer. This potentiometer controls via a fast response analog control circuit with thyristor amplifier the current magnetizing the eddy current brake.
The input potentiometer is installed in a separate hand-control housing and connected to the control unit via a spiral cable in such a way, that it can be operated from any point near the prime mover, if the control unit is positioned in an appropriate location.
A speed-stabilizing function of the MP Computer with numerical input of the desired value can be optionally superimposed to the manual speed adjustment and allows fast and precise adjustment of the speed.
Speed measurement: digital incremental pick-up non-sensitive for sense of rotation.
Torque measurement: analog measurement of the reactive torque at the stator of the brake by strain gage load cell.
The MP Computer displays the following measured and calculated values simultaneously via LED’s 20 mm high:
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Speed |
display range |
9999 |
r.p.m. |
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display resolution |
1 |
r.p.m. |
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display resolution |
0.5 |
Nm |
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calibration value |
250 |
Nm |
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or |
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display resolution |
1 |
Nm |
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calibration value |
500 or 1000 |
Nm |
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display resolution |
2 |
Nm |
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calibration value |
1000 or 2000 |
Nm |
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display resolution |
0.1 |
kW |
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(automatic change-over) |
9.999 |
kWh |
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or |
99.99 |
kWh |
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or |
999.9 |
kWh |
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or |
9999 |
kWh |
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corresponding display resolution |
0.001 |
kWh |
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0.01 |
kWh |
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0.1 |
kWh |
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1 |
kWh |
The work counter (kWh) can be set On/Off or reset.
Setting On/Off of the work counter controls at the same time the determination of the specific fuel consumption (additional equipment).
Subject to change !