لینک دانلود و خرید پایین توضیحات
فرمت فایل word و قابل ویرایش و پرینت
تعداد صفحات: 37
1. Technical Description
1.1 General Information
The transistor servo controller system series CVT is particularly designed for the triggering of equipments containing several DC-servo motors. It concerns plug-in type pulse width operate amplifiers of plug-in design (double Europe-card format). Up to six of these can be operated together with a central power supply within a cabinet frame.
The amplifier operate in the quadrant modus, e.g. the connected motor in question can drive and brake in any direction of rotation, whereby pulse moment is available for a short time, being doubled compared with the permanent torque.
The cabinet frame (assembly support) is suitable for the installation into 19"-cabinet (front installation) as well as for on back walls or bottoms of other cabinets of machines (back wall installation).
1.2 Special Features
The equipments are provided with selected efficient and reliable components and assembled using an entirely new switching technique. The following advantages result therfrom for the user:
- compact construction (storage inductor contained in assembly support).
- no audible cycle noises from the motor or the inductors (cycle frequency 8.5 KHZ: frequency of the current ripple 17 KHZ!)
- low self-warm up by using an especially low-loss out put.
- low iron losses in motor and inductors (no iron losses on standstill)
- very low minimum load and protective inductances.
- parallel operation of several amplifiers on one motor is possible.
- large range of operating voltage (60 to 240 volt) without the need to adjust the instrument.
- no auxiliary voltage required (except for the fun from 150Aeff).
- battery operation is possible (with brake energy refeeding).
- direction-defined end switches with self-acting braking.
- I2 t-current limitation is standard
- commutation current limitation individually optimizable (option, plug-in design).
- internal guard circuits for over-current, over-voltage, under-voltage and over-heating.
- complete fusing (except for ventilating fan) is provided.
1.3 Summary of Types/ Limiting Data
Type
Transform.
volt. Sec.
Initial
volt. DC
Perm. curr.
IDn
Pulse curr.
IDmax
Remark
CVT 012.3
45- 177 V
60-240 V
12 A
20 A
Without fan
CVT 012.3
45- 177 V
60-240 V
20 A
20 A
With fan
CVT 035.3
45- 177 V
60-240 V
35 A
60 A
With fan
1.5 Theory of the Function
The function of the multi axle servo amplifier system of the CVT series may essentially be learned from the following basic circuit diagrams. Figure 1.5.1 shows at first the interaction of several axles. A secured bridge connected rectifier generates from the 3-phase supply voltage an intermediate circuit direct voltage + Ucc. The level of this voltage stands in a fixed ratio to the alternating by it in the range of 60 V to 240 V.
A storage capacitor, lying at this intermediate voltage, serves mainly the purpose to keep the intermediate circuit voltage as constant as possible if short time load peaks occur.
A ballast circuit (brake supplement) being standard in the power supply, takes care that in the braking operation (amplifier returns energy to the intermediate circuit) the intermediate circuit voltage would not rise to dangerous values: on exceeding of a defined switching threshold lying a little above the open circuit voltage, a power resistor (200 W) is connected parallel to the direct current intermediate circuit). This converts the excess energy to heat. The ohm-value and the power rating of the ballast resistor are designed to agree with the requirements of the multi axle system. In cases of harder requirements (e.g antenna drive), an external ballast circuit can be connected to the direct current intermediate circuit.
A part of the power supply, the plug-in unit makes room for maximal 6 amplifier modules (inclusive of the storage inductors) and one fan plug-in unit. The storage inductors have sufficient inductivity to enable even the operation of motors with neglectibly small inductivity. Moreover, they protect the output from damage in case of short circuit of short circuit to chassis at the motor terminals. This is accomplished by reducing the ascending time in such a way that the orept can be switched off just in time.
The fan plug-in unit is required for rated currents, starting from approximately 15 A. it cools the brake resistant, the rectifier and amplifier output to a temperature which is undangerous for the continuous operation.
The function of the individual amplifier modules is shown in figure 1.5.2/3. Starting from the power supply (+U)CC, a control power supply generates all auxiliary voltages required in the amplifier. Its design guarantees a regular operation at any input voltage from 45 to 250 VDC. Any drop-out or irregular operation of the transducer will be recognized by the protective circuitry and lead to a shut-off of the output, before the descending auxiliary voltage causes malfunctions.
Two differential amplifier (NIC, NIB) record the rated rotational speed value (s) which are fed in over the input terminals 1-4. Each of the two inputs can be influenced by a potentiometer (p1, p2). Both inputs superimpose each-other without reactive effect.
The limit switch logic NIA can zero one or both polarities of the rotational speed total rated value. Thereby, the run is possible only in the opposite direction. If actuated accordingly, the motor will brake with the full amplifier current and comes to a standstill faster than with a short circuit brake. To suppress drift-off in an undesired direction, the integral control of the rotational speed control is suppressed at the sometime.
The tacho filter C16 has the task to filter off needle peaks and other HF-noise at the tacho input, as well ad to perform frequency corrections (e.g. on torsion resonance). The potentiometer p3 serves to match to various tacho rated voltages.
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