DRIVE INSTALLATION
To install the drive must be strictly followed the recommendations given by the manufacturer in the relevant Installation Manual. Examples include information provided by the equipment manufacturer MICROMASTER VECTOR. See Figure 3-15.
Figure 3-16 is information on installing a variable speed equipment manufacturer for the Allen-Bradley, AB-1305 model.
proceed to wire the inverter is Figure 3-16 which corresponds to the MICROMASTER drive.
START
To start let's take the example of two leading manufacturers of drives, with which make a comparison of its main parameters. These manufacturers are:
SIEMENS with your drive model: MICROMASTER VECTOR, and ALLEN-BRADLEY with your drive model: AB1305
Main Parameter .-
Analysis of some parameters .-
1. Boost Voltage .- In Figure 3-11, when fed to the motor with V / f constant, it appears that no loss of torque at low speeds' (frequencies below 15 Hz). To overcome this problem applies an additional voltage to the V / f managed to increase the torque curve for this region of low speed. This technique is known as the "Step Voltage" or, in English as "Boost Voltage".
Then, in Figure 3-17 shows the parameter "Boost Voltage" in the 1305 Allen-Bradley equipment
It is noted that the parameter "Boost Voltage" is adjustable according to the requirements of the load and only for low speed takes precedence.
2. Compensation Slip .- In Figure 3-11, shows that there is a sliding block calculation ("slip" in English), whose output is added to the frequency reference value. This is because there is no speed feedback and know that the engine rotor slows down as the load increases. Therefore, there is a proportional relationship between sliding and loading. The higher the load, the higher the slip and therefore the motor speed decreases slightly from its previous value. Which is manifested in the drive as if the engine failed to respond to the command given by keyboard velocity.
AB1305 in the drive, we have the parameters "Nominal Slip" (Rated Slip) and "Isolation Additional Compensation" (Slip comp. Adder), which is responsible for preventing such loss of speed. The MICROMASTER inverter, it has the parameter "Slip compensation" that is responsible for the problem studied.
3. PWM Frequency. - Is the "frequency modulation" or "Carrier Frequency" and its default value is 4 kHz. This sets the working frequency of IGBT transistors. The purpose of adjusting this parameter is:
Work silent, then this parameter is set to a higher value.
Increased distance between the motor and the drive, then the value of this parameter should be decreased.
The consequences we have to increase the frequency of the carrier is:
Increased losses in the converter, which should be applied to reduction of power on the drive as shown in Figure 3-18.
Increased emissions of radio frequency interference (RFI).
4. Skip Freq. - Called "Frequency inhibited" in the MICROMASTER drive and "frequency hopping" in the AB1305.
Its function is to avoid the effects of mechanical resonance of the system to certain operating frequencies of the drive.
frequencies are suppressed to give the drive motor, fall within the parameters. Therefore it is possible stationary operation within the frequency range suppressed.
This parameter works in conjunction with another that will provide the width of the forbidden frequency band.
There is possibility of banning three frequency bands.
