Isolation of a VSD is necessary and can be realized with a line contactor or an isolator. A contactor has the advantage that it can be switched electronically and can be controlled by a safety switch (ie included in the emergency stop circuit). It also disconnects the VSD from supply when not in use and eliminates potential damage resulting from disturbances on the supply.
All VSD’s generate harmonic currents. This means that the input current is not completely sinusoidal. For small drives this can be acceptable as the effect on the supply network is smaller, but for high power drives (sizes S50 and above) an input choke is required to reduce the harmonic currents. In some areas where there are specific restrictions on supply quality, input chokes or specialty harmonic filters may be required.
The ferrite ring is used when the VSD is used for residential and commercial purposes (First Environment). It is installed between the output of the VSD and the motor by passing the three phases through the centre of the ferrite.
Output choke is required for long motor cables, multiple motor applications and may be beneficial to old motor installations. It can reduce reflected waves and dV/dt to the motor. For sizes S50 and above, output choke is recommended.
The Sinus Penta has IFD, VTC, FOC and SYN control:
• IFD (Inverter Frequency Drive)
This function offers an adjustable V/f pattern for general purpose applications.
• VTC (Vector Torque Control) Open Loop
Through Sensorless Vector Direct Torque Control, the VTC function allows for improved torque performance without the need for feedback.
• VTC Closed Loop
THE VTC function allows for fast dynamic response through encoder feedback for high torque or demanding applications.
• FOC (Field Oriented Control)
FOC is the ultimate in vector speed control providing high accuracy through encoder feedback for high torque precision and a wide speed range.
• SYN (Synchronous)
This control application provides a vector function for the control of brushless synchronous permanent magnet motors. This provides high torque accuracy combines with energy efficiency.
The maximum cable length is a factor of the drive size. Elettronica Santerno provide recommendations on the maximum cable length without the need for an output choke. For longer lengths it is recommended that an output choke be included. Refer to the user manual / catalogue.
When an output choke is used the cable length is only restricted by the voltage drop that is obtained from long cable runs. For some applications where a reduction in voltage at the motor terminal and hence reduced torque will be a problem, it is best to reduce cable lengths as short as possible.
For new applications, it may be difficult to tell before you actually test a motor / drive solution. In general some applications can rely on system losses such as decelerating force, or otherwise can tolerate a long deceleration time. However, applications with a combination of a high-inertia and a required short deceleration time will need dynamic braking. If unsure, please contact NHP and calculations can be done to determine if dynamic braking is needed.
Flux is the measure of the magnetic field produced in the motor. It is measured in Webbers (Wb). In order to produce torque at the motor shaft the drive must first establish the magnetic field by producing flux. In larger motors this process can take a few seconds and therefore can be more critical. The fluxing function provides the motor with a static current to magnetise the windings without developing torque (to allow the shaft to remain stationary). This way when the start signal is provided the motor is able to produce torque immediately rather than magnatising the windings and then producing torque.
By setting C183 (Fluxing Max Time before inverter disable) to 1ms, this will cause fluxing to activate momentarily on power up and remain disables at all other times. Please note a setting of zero for this parameter causes fluxing to remain on continuously when in standby.
No, because this will stress the input rectifier and, precharge circuit of the drive and eventually may damage the drive. It is better to use the start on the Multifunction Digital Inputs or the keypad.
The Sinus Penta has a Remote Mounting Kit for the keypad with either a 3 meter or 5 meter cable. This allows easy installation of the keypad on the front of the cabinet with protection of IP55.
As standard the Sinus Penta incorporates a Modbus port. For other fieldbus types an option board can be added to provide this communication. The protocols supported are;
• Profibus DP
• DeviceNet
• Interbus
• CANopen
• ControlNet
• Ethernet
Semiconductor fuses are recommended to significantly reduce the damage to the drive in the event a short circuit develops within the VSD. This may be the result of poor environmental conditions or ingress of foreign objects. They are not required for proper operation of the drive itself, however, it is advised that semiconductor fuses be used.
It is not recommended to do this as the bottom drive will push heat up to the top drive resulting in excessive temperatures for the top drive. It is suggested that drives be mounted side by side or the air flow of the two drives be segregated to ensure that there is no transferal of heat.
Using a 4-pole motor will work for most applications. The Sinus Penta can be configured to operate motors from 1 rpm to 3200rpm. The greater the number of poles, the slower the top motor speed will be, but it will have higher torque at the slowest speed. The number of poles that a motor has determines its speed at a particular frequency. The synchronous speed for 3 phase 50Hz motors are as follows:
2 pole = 3000 rpm;
4 pole = 1500 rpm;
6 pole = 1000 rpm;
8 pole = 750rpm;
etc…..
Yes, this is possible.
For pump and fan applications, the following restrictions must be observed:
• The total motor current should be smaller than the Sinus Penta output current.
• All motors will run at the same speed.
• An output choke is required.
• A high starting torque is not possible
• Auto tuning is not possible.
• The drive does not provide individual motor protection
Yes, the standard Sinus Penta drive can be converted into an active rectifier. This drive can be connected to a standard Sinus Penta operated as the output stage and is connected to the motor. This configuration also requires additional input filtering.
An active front end drive incorporates IGBT (insulated gate bipolar transistors) technology in place of diodes for the rectifier. This is the same technology used in the output stage of the drive. Unlike the diode rectifier which only allows energy to flow in one direction, by using IGBT front end, the drive can actively control the energy flow in both directions. This provides a number of benefits including the following
• Allows full regeneration.
• Provided extremely low harmonic distortion.
A drive is used to control the speed of a motor. This is represented in RPM and therefore it is this value that needs to be controlled. In older drives were control was done using a fixed voltage to frequency ratio rather than vector control, it was frequency that was used directly to control speed. Now with features such as sensorless vector control, slip compensation and flux control, Hz is no longer an accurate representation of speed. For this reason Elettronica Santerno use only RPM as the speed command even for their IFD control.
The maximum operating temperature is 40oC for the Sinus Penta. However, operation above this temperature is possible but requires the output current to be derated by 2% per degree Celsius. The temperature can be increased to a maximum of 50oC.
No, the Sinus Penta incorporates thermal modeling which can be used to provide this protection. This must be configured to match the motor installed to provide optimim protection. Alternatively it is possible to integrate thermistor monitoring for best results.
Due to the robust design and Elettronica Santernos’ ISO9001 quality controlled manufacturing, NHP is able to offer a three year warranty for the full range. This warranty provides peace of mind for installations large and small. The warranty terms are as indicated in the Terms and Conditions of Sale.
The Remote Drive software provides full connectivity between the drive and a PC. It provides parameter navigation and storing along with monitoring, trending and control. This software requires a connection kit which is available from NHP. The software is available free of charge to NHP customers and can be downloaded from www.nhp-online.com.au. A demo version is also available from this web site.
A unique feature of the Remote Drive software is the remote access function. This allows an external person to connect to your drive remotely from anywhere in the world via an internet connection. With a drive connected to a local PC and linked to the internet, one of NHP’s engineers can access your drive to provide remote assistance with parameter setup and fault diagnosis. Please contact NHP for further details.
As with all NHP products, full support is provided for this new range nationwide. With the largest network of offices in Australia there is support close at hand.
