Wangeshi Machinery Equipment Co., Ltd.
extrusion drives: time for a change?
C motor and electronic equipment being manufactured a-
For extrusion applications, the C- disc packaging is more attractive.
A basic advantage is simplicity. c motors.
Three in commonphase a-
The induction motor usually operates at a fixed speed controlled by the basic operating frequency at 60 Hz in the United StatesS.
Electronic drive, called inverter, will be 60-
Convert Hz power supply to variable power supplyfrequency a-
C, then the motor speed changes directly with the frequency at which the inverter supplies power to the motor.
A- A more obvious advantage
Robert Green, president of C- said motor technology has the potential to reduce equipment downtime and maintenance costsTAC, Inc. , an a-
C auto supplier in Cleveland. A-
C. The motor does not have a brush or a diverter, which may be the source of the fault in the traditional bushingtype d-c units.
In the plastic processing environment, d-
C. Motor failure usually results from one or more of four situations: * the large amount of cooling air required may pollute the open air, Green saysframe d-
Motor with dirt, moisture or corrosive chemicals.
* If dirt accumulation is allowed, a filter that cleans the cooled air may reduce air flow, resulting in overheating and winding failure.
* If poorly designed, pipe works that provide clean air to the motor may reduce air flow and cause the motor to heat up and shorten the insulation life.
* Finally, due to the lack of daily maintenance, the brush will wear and tear, resulting in the failure of the adapter.
Green claims a-
C. Compared with the brush, the motor has certain advantages in cooling devicetype d-c counterparts. In d-
C. Motor, most of the heat is generated by the stator (
Inside the motor;
Therefore, the motor is usually cooled by blowing air through the motor.
This provides an opportunity for contaminants such as PVC dust to blow through the motor housing, resulting in damage to the brush and winding. In self-ventilated (a-c or d-c)
Motor, the fan connected to the shaft provides a proper amount of cooling air for the highest speed.
But if the motor is part of the adjustable motor
During half-speed driving and running, the airflow decreases, causing the motor to overheat.
Completely surround a brushtype d-
C motor to prevent dust is possible-but expensive -
Another option, according to Green, is because it is inefficient to remove heat from the winding.
But, he pointed out,
The induction motor with a fully enclosed frame is ready-made and affordable. A-
Can be completely closed, non-ventilated (TENV)
Or a fully enclosed hair dryercooled (TEBC)versions. In TENV a-
C motor, cooling is radiating heat through the frame.
This is slow.
Speed overheating problem because the cooling is not dependent on the speed of the motor;
But they usually require a larger frame size, which limits their cost
The effectiveness of the small horsepower range.
On the other hand, it is reported that the TEBC motor is very suitable for extrusion applications.
Instead of axis-
Installed blower, increase or decrease the speed and airflow as the speed of the motor changes, such as in
TEBC a-ventilation motor
C. The motor has a blower driven separately.
The blower operates at a constant speed to provide a uniform, continuous flow of cooling air.
Other features may include provisions for the internal thermostat and the installation of the tachometer.
Green admits that the recently expanded brushless d-
C. The Motor entering the higher horsepower range also eliminates the traditional d-
C motor, but added, brushless d-
Unit C still has the possibility to breathe in the open frame of dust.
\"The winding is affected by the same deterioration problem as the brush --type d-
C. Motor and d.
C. The motor is much wider and more expensive than the-motor, and the maintenance cost is higher
\"In fact, the minimum downtime and low maintenance costs are said to be a-
C. Variable frequency motor.
Green claims that the repair of the winding tends to be less labor intensive and less costly, and it may take a few days to replace the winding
A few weeks on d-c brush-type motors. A-
In addition, he said, the performance of the C drive
C the drive can equal or exceed the performance of a comparable brushtype d-c drives.
The least complicated d-
The C driver adjusts the speed in the range of 2% to 5% (
Stator voltage regulation).
The speed meter with moderate cost provides brush-type d-
C motor speed regulation with a maximum speed of 1%.
This can be increased to 0.
The 1% comes with an expensive tachometer and 0.
The digital tachometer is more expensive at 05%. A-
The C drive provides strict control at no cost to the tachometer. The simplest a-
C drive including slip
The compensation circuit provides a speed adjustment of 1% at a speed ratio of 10:1, usually from 6-to 60-Hz operation.
Use 120-this range can be extended to 20:1
But the minimum speed is still limited to 6Hz.
An extra advantage is a-
C drive is not affected by \"positioning\" at very slow speedtype d-c drives.
For higher performance, an openloop, flux-vector a-c inverter -
Upgrade of standard pulse-width-modulated (PWM)a-c inverter -
The working range of 100:1 is provided, and the speed adjustment is 0.
5% in the 10: 1 speed range without the tachometer.
Speed Regulation of 0.
05% can be closed from-
Loop speed regulation and digital tachometer on motor.
Traffic, Green claims.
Vector inverter in high-
Performance extruder and downstream applications. A closed-loop, flux-
The vector inverter plus TEBC motor and digital tach can provide complete dynamic response control, a speed range of 100:1 and 0.
05% speed regulation.
One production a-
The c drive standard on the up to 75 hp extruder is the crown machine Div.
Sick west of Chicago
According to Michael Chumura, Crown\'s extruder product manager
Maximum standard security speed for C drives-
Basic motor speed of 200%,125% for d-c brush-type drives -
This increases the flexibility to run a variety of products.
The Akron extruder at the Fulton canal in Ohio reported that it also provided
50-c driver on main extruderto 75-
Hp series, good results. A-
C. The inverter driver may be more economical than the brush-type d-
The power factor of the c driver is reported to be good, especially at lower speeds. A-
C The inverter is said to keep the power factor at about 0.
97 at all speeds.
In contrast, Green says the power factor of traditional d-
The C driver changes with the speed of the motor from 0.
87 is 0 at the highest speed. Half Speed 4. A-
C. Limitation and success
C drivers also have inherent disadvantages in constants
Tractors say torque applications such as extrusion.
One drawback reported here is the low start torque, which creates slippage when the speed is close to breaking through. D-
The C driver has a high starting torque at 0 rpm.
Some of the drivers counter that electronics can overcome this disadvantage.
Dan cassage of Emerson Industrial ControlY.
Claim many a-
Today\'s c drive is equipped with \"automatic\"
The boost \"function that automatically raises the voltage to compensate for the increased current consumption.
\"With a new power supply, a-
The performance of the C drive is getting closer to d-
C. Low cost of motor.
\"Other people warn to use a-
C drive, especially if a-
No variable test on c motor-frequency duty.
Brian McMahon, product manager, Reliance Electric
Cleveland said, \"you need to be careful to form a Drive pack to make sure the motor is designed for variablesspeed duty.
\"An application that has been proven to be successful
C. The driver cools in the air ring and internal bubbles (IBC)
Some systems for blowing film lines.
According to Matthew Bennett, the advantages herep.
Reifenhauser film system, pebodi, Volkswagen. It\'s a-
The C inverter drives the control airflow by changing the speed of the impeller rather than generating a pressure drop through an obstacle.
Therefore, it is reported that these drives can reduce the temperature rise by 10-15 degrees F.
Filman, Fairfield, New YorkJ. Also provided
C. The inverter drives the standard of the application on its line.
Another area of A-
The drive may have potential in extrusion control.
Some extruder manufacturers predict that digital drives will be used more because of their higher accuracy and the ability to connect to production lines
Extensive control system.
Of course, digital technology applies to bothc and d-
But some extruder manufacturers say a-
The C drive may have edges.
For example, Bangert of Reifenhauser has seen some shortcomings of the brushtype d-
C. The technology to connect all drives together, adding that the digital a-
C drives may have potential in this regard.
Louis Ferrers, marketing director, Louis/Davis-Standard Div.
Crompton and Knowles
Boca RATCH, Conn.
Make some a-
C drive suppliers in Milwaukee-based Allen-Bradley Co.
Provides a good driver integrated with the programmable controller, which makes the system easier to design. A-
Traditionally, the cost of the controller
C. Electrons are more complex than d-electrons
C drive, make a-
The C drive system is more expensive.
One of the cost contributors here is a-
Dual power conversion is required for the C drive.
Some suppliers say there have been two recent trends that are closing the price gap.
First, the microprocessor eliminates a-
C controller and convert it to software.
Second, transistor, power element in a
C drive, now have a higher current-
Carrying capacity than before. C-
TAC\'s green reference.
The housing cost survey conducted last year compared a-c and d-
C system from 11 different drive manufacturers including controller, blower and motor.
He claims a-
C systems are now usually cheaper under 40 hp at a price from 40-75 hp.
He believes that the cost advantage will begin to shift the marketc drives. BRUSHLESS D-
C. Another alternative driver to replace the extruder, brushless d-
C, claimed by Powertec of Charlotte, New YorkC. -
The only major supplier of these drives in a higher horsepower range-
Combine the best features of a-
C plate and brush-type d-c drives.
The company recently expanded its products from 1/2 hp to 300 hp. Unit C, like a-
C. Motor, almost no maintenance is required.
It is said that the c driver provides 0% speed error through digital phase
Lock the circuit with a speed range of 100:1.
In a brushless d-
C. Motor, winding and magnetic field with the usual d-
C arrangement: place the winding towards the outside and place the magnetic field of the motor on the shaft.
This configuration allows the field to be turned instead of the winding.
It is reported that one of the benefits here is more effective cooling because of the heat
The production element faces the outside of the motor.
It is said that the efficiency is high enough to accommodate smaller frame sizes. Brushless d-
C. The motor eliminates the magnetic field of its brush-type d-
Correspond by placing a permanent magnet on the shaft.
According to Powertec v. , there are several advantages in placing the magnet on the shaft and rotating the magnetic field instead of the statorp.
Selling Ed Lee: It reduces the inertia of the rotor and also eliminates the brush.
Force the current to the right winding (
Auto-complete on brush d-c motor)
, Brushless d-
C. The motor uses the encoder to read the position of the shaft.
Have an advantage over a
C. The motor is stated in the waveform used by the brushless d-c motor.
The C- stator operates on a ladder shape, while-
The C stator is designed to operate under a sine wave current.
In the trapezoid waveform, when the power supply is turned on, the current forms a level and operates stably at that level;
When the current is off, it will decay back to zero.
According to Lee, the practical benefit of doing so is that it is possible to achieve a phase change with a simple electronic device. BRUSHLESS D-
C. The performance is brushless d.
The C driver is of high starting torque ,\"
A c drive with a given horsepower will be better than a brush-type d-
C horsepower is the same in terms of starting torque, \"Li said.
\"Usually, you get a 170% rated torque when separating.
C. The Motor will not have a hot problem at very low speed, Lee pointed out that this is a-c drives.
C The drives do not produce slippage, they are reported to be running slowly at high torque and there is no overheating problem.
In addition, the permanent magnet used in the brushless motor eliminates the magnetic field excitation that generates heat in the brushtype d-c motor.
High precision is considered an inherent feature of brushless d-c drives. Brushless d-
C. The Motor adopts an encoder for phase change;
So, according to Lee, their nature is easily adjusted by digital speed.
In this way, the shaft accuracy of the DC motor can be improved.
C The motor has a large change in load and an error of 0%.
More important for the extruder, long-
Term drift of brushless d-
The C drive is specified as 0.
5%, usually 0. 2%, he adds.
This precision can be matched by a brushtype d-
He pointed out that the c driver has a good tachometer, but it is the standard function of the brushless d-c units.
In addition, the impact load or significant load change is important in many downstream operations, which may benefit from a brushless d-c drive.
Lee claims high power factor for brushless d-c drives -0. 95 to 0. 98 -
Better than two brushes-type d-c and most a-
Inverter drive. Unlike brush d-
C drive, no power-
Penalties for factors below the basic speed of operation.
The input current controlled by the brushless motor is said to be proportional to the output power of the motor shaft, a product of speed and torque.
Lee claims a-
The power factor of the C driver is high.
He explained that the power factor is the ratio of the actual Watt to the apparent power (kva)
, When the current and voltage peak at the same time and have the same waveform, a good power factor is generated. In a-
C driver without input inductance-
Many people have different wave shapes. In a-
C driver without input inductance-
Many people, he said.
The current and voltage peaks at the same time, but the waveform is different.
The current waveform is not sinusoidal, and although the current waveform is in phase with the voltage waveform, the actual power factor resulting from it is very poor.
Li said that the improvement of magnet technology makes the DC motor
Use c drives more widely.
It is reported that this improvement improves the reliability of permanent magnets and reduces the cost, thus reducing the manufacturing cost of brushless motors.
He claims that the unit is a unit, a brushless d-
C motors are now cheaper than their brushes-
5 models corresponding to hp and above.
Although he says there is no actual limit on the brushless d-
C. Motor size, Lee admits the power limit
At present, the Switch device limits the controller with reasonable price to 300 hp.
Nevertheless, he predicts that breakthroughs in this area will expand
At the beginning of next year, cdrive\'s products reached 500 hp.
Some extruder manufacturers have reported using brushless d-
C drives in various applications.
Killion extruder, Inc.
Cedar Forest, New YorkJ.
, Provides brushless d
C. Drive from more than 5 HP as a free choice for customers. HPM Corp. , Mt.
The Ohio City of Gillette has launched a 40hp brushless d-
C. New 2 1/2 standard drive-in.
The extruder, and said it would make the brushless drive standard on all devices below 125 hp.
Robert Bessemer, product manager for Killion downstream devices and systems, reported that he saw an increase in requests from customers to improve speed accuracy over a wider range of speeds.
As a typical example, he points out that the smaller extruder tends to have an optimized Screw for specialized applications such as medical tubing.
While one may question the value of the precise drive on the extrusion, he believes that the extra accuracy of the drive, combined with the proper screw design and good temperature control, it is true that there can be significant differences in performance.
Line product manager, Yigen machinery division.
John BrownN. SomervilleJ.
C. The driver has potential in downstream devices, such as the vertical cooling stack of the cast film line.
\"We found that customers want to produce in a very wide speed range from 1-
Up to 40-2 grinding products50 mils.
Advantages of brushless d-
The C drive is that they can have precise control over the entire speed range \"without using additional gear boxes and transmissions.
Another potential application, he added, is the roll stack used for plates with high surface finish because of the brushless d-
C. drives eliminates gears that may pass the ripple effect of \"chatter\" to the surface of the product.
Though Smith says d.
C drives are a little more expensive than their brushestype d-
He added that the difference was offset by a reduction in mechanical equipment such as gear boxes. NRM-
Steelastic in Columbia, Ohio initially had a signal problem with the tach response, when it first installed a brushless d-
According to Timothy warmer, a process engineer, c runs on the paper production line in the lab.
He quickly added that these issues have been corrected and the drive is working fine now.
The company has now done 40-hp brushless d-
C driver standard on its 2 1/2-in. profile line.
Womer thinks the brushless d
The C drive works fine, but adds that the motor should be in the right size in order to meet sufficient torque requirements.
And the wide speed range on the brushless d-
The C drive provides the possibility to replace the gearbox, and the motor must be larger in order to make up for the torque loss in the gear drive.
In a custom form application, the machine may still need right-
If running in a very low speed range, the angular gear reducer is designed as its power base, he added.
Time to change?
Although the-manufacturer claims
C and brushless d
Not all extruder manufacturers are ready to cancel the brushtype d-c systems.
One drawback of two brushless d-c and a-
According to Faillace of HES/Davis, it is difficult for the c inverter driver to measure the power consumed by the driverStandard.
Winding current of electric brushtype d-
C drives are easier to monitor.
This can be a minor issue in normal production, but this is important if the extruder is used to test the new resin or screw design.
John Rupert, sales manager, Maplan Services Div.
McPherson Kans. , says that a-
Due to possible heat problems in the low speed range, the potential extrusion of the c drive may be limited.
One recent trend, he noted, is thatc and d-
Motor supplier reducing frame sizei. e.
, Upgrade the motor to a higher horsepower in a smaller frame. \"A-
The energy still has to go somewhere if you drop the speed, which is still a problem --
It gets into the extra heat. D-
C does not have this problem because it will react to it if you add voltage to it.
So the natural d.
C more efficient.
\"Frank Nisser, president of WelexBlue Bell, Dad. Expected brush-type d-
C drive will continue to dominate extrusion due to its wide range of availability and costCompetitive power.
He was enough to prove that a-c controllers.
Although he admitted d-
He said they did a good job with c drive. of-a-
In fact, it is a responsibility to design kindly.
\"It\'s a great product,\" he said, \"but it\'s so unique that it\'s notInterchanges.
If the car burns out, you have to go back to a supplier.
\"Single source of large brushless d-
The C driver is clearly a concern for other extruder manufacturers.
Robert Higgins of the Alpine American company, Natick, Mass.
\"Engineers are looking for easy-to-repair drives and easily accessible parts.
\"In his view, the United StatesS. -made brush-type d-
C drive is in compliance with the act.
He predicts that digital technology will become more popular on screen brushing. type d-
C. Provide a better drive package for membrane blowing line control.
Finally, John Malinowski
Product Manager of Ark Fort Smith Baldor.
Two brushes are provided-type d-c and a-
C. Drive the inverter and point out other alternatives to make up for the shortcomings of the former.
For PVC extrusion applications, special brushes can be obtained at very little extra cost, which have a slight grinding effect to scrub the diverter and prevent corrosion.
In addition, he added that the cooling air discharged from the outdoors is an effective way to prevent the motor from being contaminated internallyplant dust. Brush-type d-
He said the c drivers have an advantage in extrusion applications because they provide constant torque throughout the entire speed range required for the extruder. A-
He said that the C inverter has a more limited torque range at lower speeds and may require an oversized motor and drive.
\"The cost reduction of the inverter has an intersection --
Effective than d. c drives.
\"He also minimized some of the shortcomings of the brush --type d-c motor repair.
He admitted that the motor with a laminated frame could be artificial --
But he added that some d-
C. There are bolts in the motor supplier-
In areas that are easily replaced.
In addition, he said a higher degree of technology may be needed to repair the feedback sensor on the demagnetic rotor or brushless d-c motors.
Broad availability is another advantage.
The motor and the controller can be exchanged on the brushtype d-
C system, it can make it easier to change the motor and drive.
It is said that the c driver, which can now provide up to 300 hp, provides a speed error of 0% through digital phase locking, with a speed range of 100:1. (Photo: Powertec)PHOTO : A-
C. There are few moving parts of the variable frequency motor, and it is reported that the wear and maintenance of the standard d-brush are eliminated. c motors. Reduced a-
The price of the controller makes these drives more competitive.
Picture: brushless d of Powertec
C The Motor consists of ceramic magnets permanently bonded to the shaft, simple stator windings, digital position and speed sensors, and fins for heat dissipation.
It also provides blower cooling.
Photo: Above: standard d-though-
C drive continues to dominate extrusion, a-
Progress can be made with the c driver integrated into the programmable controller. (Photo Davis-Standard).
Left: brushless d
The C drive provides independent control for each polishing roller on that multiple drive
A configurable sheet line for HPM to prevent overheating.