Contactor before or after vfd. Schneider Electric Global .

Contactor before or after vfd The VFD also has built-in overload protection and motor start/stop control functions. My question is, after reviewing existing soft start and VFD applications at various locations, I would like to know what the reason would be to keep a contactor in the circuit? I don't see any rhyme or reason for the different schematics which use the control circuit to power the A1 and A2 of the drive which I think would cause the drive to have to power up each time. This publication explains some considerations for the selection of MPCBs. 5kW three phase 220VAC motor (because the next smallest size was for a 1hp). This must be rated to close the VFD starting current, and interrupt a current slightly higher than the nominal VFD current. Contactor estático: contactor construido a base de tiristores. 1. 2 to 1. Our Safety Contactors Weg’s CWBS series of safety contactors have mechanically linked contacts (IEC/EN 60947-5-1) and mirror contacts (IEC/EN 60947-4-4) that allow for safe operation of machinery and equipment. It looks like (from the link below) that he's using: MCB Magnetic contactor AC reactor (he External braking resistors may be required for high inertia loads and/or rapid deceleration. There are both physical and electrical installation basics to be aware of when using a VFD. Contactor hidráulico: se acciona por la presión de aceite. I read on another thread here that if So the SAFE BET is to not install a disconnect (or contactor) on the output side unless you are ABSOLUTELY SURE you know what you are doing in programming the VFD. Solutions for Motor Management. Stop category 1 removes power from the load once it reaches zero (disconnects IGBTs). A selector switch labeled "VFD--OFF--BYPASS" selects these when set to VFD. For this reason a reactor at the input to the drive may be of some help, but a better solution would be to attenuate the After that I installed a contactor before the VFD. Thread Starter. However, sometimes the 2nd motor will have to stop before the 1st. These bypasses are ideal for facilities that run 24/7 and can neither afford downtime nor wait for after-hours repairs, such as a big-box store or casino. Some people here are of the opinion that we can turn off the contactor pretty much straight away. 5 hp Bridgeport and purchased a TECO Westinghouse L510-202-H1-U VFD to drive it. Both are designed to minimize system downtime should the VFD fail. Residing in the control cabinet and wired before the VFD, a reactor will smooth out the waveform of the incoming voltage and, at the same time, smooth out any ripples in the current draw. Posted October 23, 2017 by springercontrols. Get support to configure, troubleshoot, update or upgrade your motor management solution built with Altivar variable speed drives and Tesys devices to start, control, protect and monitor Low Voltage and Medium Voltage motors and loads, covering direct start, soft start and variable speed control. So, is there any reason I need an MC between the MCCB and the VFD? • Refer to the VFD User Manual for the listing of approved branch circuit protection devices and their sizing recommendations. We even recently got a new guy, that didn't check for I've been following Clough42's videos on sorting out a VFD with a lathe and trying to figure out what I need, electrically, before and after the VFD. The contactor before method usually shorten the VFDs life due to powering down the VFD during estop. Looking at their recommended circuit they show the starter coil of the magnetic motor contactor connected to an alarm contact on the VFD. 4 - you want to make sure that the second contactor can't connect or disconnect a second load while the VFD is powering the first. They sent some sample drawings of their existing machines. Yaskawa VFD; Teco Westinghouse; Understanding Motor Controls: Starters, Contactors, Overloads, A 4-pole contactor is commonly used in standby power systems, If excessive current is detected, the overload relay trips the circuit, stopping the motor before damage occurs. Right. If you are connecting to a dedicated socket withe a 30A breaker, then should not need to fuse at the machine. Contactor neumático: tipo de contactor que se acciona por la presión del aire. The main reason is that: if an output contactor is It’s true that opening a contactor under load on the output of a VFD runs a risk of damaging the VFD. Adisconnect between the motor and drive is NOTRECOMMENDED. A category 0 stop is instantaneous and has priority but is Variable Frequency Drives (VFD). The VFD will be providing all protection for the motor. In previous blog posts, we talked about the differences between IEC vs. Perhaps you would enlighten us as to what a typical "arc suppression system" would be on an AC, HP rated contactor. I think I have seen before VFDs had the safe off feature (estop) that people put contactors either before or after the VFD. 5 times the nominal VFD current. To use a VFD just for starting and braking a 690V, 300kW motor that drives a high inertia load. Yaskawa Electric America, Inc. What's wrong with this setup? It previously used a contactor controlled by Siemens Simocode and a Siemens PLC. If the built in disco incorporated in the control does not allow for safe work on the control, then a line side disco is required. Then all controls are with the remote wiring, the lathe is powered all day then I turn it off at night. The last element to consider will then be the control element, which can be a contactor or switch. I am looking at a system that consists of multiple VFD's each driving a single 1HP (or less) motor. Thread starter claudio; Start date Nov 15, 2002; Search Forums; New Posts; C. La potencia disipada por este tipo de Does the contactor in series with the 3-phase power break supply via physically opened contacts, of the 3-phase power to the machine (before or after the VFD doesn't matter), yes or no? It is allowed to use a "safe torque off" implementation in accordance with ISO 13849-1 and the appropriate PL in accordance with the risk assessment as a protective-stop function. Yes it would be in banks. Output would then go to VFD. Being that there will still be one motor connected If safety is required then the VFD should have a contactor (or 2) driven off the main safety relay, this can be before the drive (and im most cases nowadays) after the drive, you should not rely on the electronics to stop the drive in an emergency. Similar designs of different brands were A motor branch circuit, including a Variable Frequency Drive (VFD) and one or more Motor Protection Circuit Breakers (MPCBs), is a complex system and its performance depends on all components, devices, configuration and their interconnection. However most electricians I know don't wait that long. If you are going to have a contactor between the VFD and motor, you will need to shut off the VFD's output before opening the contactor, otherwise there is risk of damage to Using a contactor on the load side but only switching it when the VFD is off is not a problem at all. Date: 12/21/2020. 03 10/1/06 Page 1 of 2 CB L1 L2 L3 M OL T1 T2 T3 * * COMBINA TION STARTER W/ CIRCUIT BRKR, CONTACTOR AND One way of filtering out surges from the electrical system before it is conditioned in a VFD is with a line reactor. I do pull 4 wire single phase to my machines, so I can pull off 1 leg (before the VFD, after the fuse) for 120V. An ohm meter can be connected to the auxiliary contact Multiple AB PowerFlex 40 Drives, in a Packaging Line Control Enclosure (bottles, cans, cases, pallets). claudio. How to Select and Size an IEC Contactor. The VFD then executes a coast-to-stop preventing any damage to the disconnect switch and the with Integrated Break Before Break Auxiliary Contact Amp Description Non-Metallic Stainless Steel 30 Circuit-Lock disconnect switch for use with variable frequency drives. The VFD input will be single phase 220VAC and was sized to accommodate a 2hp 1. Investigations showed that MPCBs rated lower than 10 A suffer most. On a couple of SIL-3 applications, I have seen Safe/Stop, Safe Torque off, used with an additional contactor downstream of the drive along with an encoder. The contactor is first disengaged after the drive has come to a complete stop. The only reason some mfrs list their VFDs to be protected by MPCBs instead of MCCBs is when the VFD mfr does not manufacture their own MCCBs. The theory is that the VFD is less reliable than a starter (yeah, right). If it is some relay, or bi-metallic unit, it is likewise normally rated for around 1. A 2 contactor bypass will remove power from the drive When a VFD controls a motor and does not need to switch between the power supply, an output contactor is not needed to be connected between the variable frequency drive and motor. They demand dual safety contactors in front of the VFD's. The contactor after method was used when the VFD ramped to a stop the PLC opened these contactors. The device on the line side only sees the input current of the VFD, which is lower than the output current, so it means nothing with regards to the motor. That’s the quickest way I know of to blow up a VFD. I've never done anything like that before usually I just let the VFD do the overload and oc protection but with multiple motors they'd have to have individual starters and fuses for disconnects on all of them. After reached a proper speed at starting, motor is connected directly to the line short circuiting the VFD. Another issue, and what I have seen as the most common failure mode in the VFD's I use is too rapid cycling of the power after the VFD is turned off. A contactor after the VFD: Off course the normal starting AND stopping is via the VFD. Location UK. google category 1 stops. Schneider Electric Global. So that means if you have a known procedure of If you use a contactor before or after the drive look at using a safety relay with an off-delay timed contact to control the drive contactor, and used an instantaneous contact for the drive enable. Placing the motor contactor before the breaker would protect the motor and the field wires in the event of a short or ground fault. R HV Ba er y 3 - You have to energize the contactor and wait a few milliseconds before telling the drive to spin up the motor. applications, you can use one variable-frequency drive (VFD) to control multiple motors. First we have a breaker, a contactor, a VFD, and another contactor all in series. However, they are using a LC1D09BD for example, which is not a safety rated contactor. AR. There are however at least two main dangers of putting a contactor on the load Contactors are typically used in HVAC and pump applications when down time of the motor in question is unacceptable. Look at manufactures for elevator drives. Cycling any contactor on the load side of the VFD during operation will surely trip the control. The document has moved here. This is to allow the contactor some settling time. Otherwise, they can cause nuisance tripping. A stop signal to the drive then a couple of second delay before opening the contactor. Less acceleration can soften the mechanical forces at motor start and reduce inrush current. About the Author . The Semiconductors are exposed to whatever line voltage condition exists. Besides not running motors off of a contactor after a vfd, you would need to protect each motor with a separate overload device, and tie each one to the vfd will start and stop both motors simultaneously. Jul 22, 2009 No. Moved Permanently. If this works what would happen if you pressed the off button on the saw? This would open contactor and cut power to the cannot protect the converter from a voltage spike since a link choke is located after the converter (refer to figure 1c). After the pre-charge state, the pre-charge contactor opens and the HV positive contactor closes to drive the system or charge the battery. Some VFD’s don’t react well to the output opening while it is running and I don’t know of any that will allow you to switch in a load after it is running. Can you use the contactor before the VFD? Turn on power to the VFD using the original switch? Input power to contactor would be 1 phase 220v. I don't have any external equipment such as braking resistors. Selecting the right contactor for Variable Frequency Drives involves careful consideration of electrical compatibility, coil design, contact rating, VFD does essentially replace a motor starter in applications where they are used, there still can be control schemes where a contactor may be used to interrupt power - typically only for occasional shut down situations and not as a routine control method - VFD's don't play well with contactors in the circuit, total loss of supply power is not so much of a problem as A contactor or disconnect switch between the VFD and ac motor is not recommended. In the applications that I have seen the E-stop removes the enable signal to the VFD or deenergizes a contactor that goes before the VFD but I dont know about how convenient is this second option. You should wait at least 5 minutes after the VFD is switched off before it is power back up. Problem is that I can completely shut off power to the VFD with the MCCB. This contactor is open while in VFD mode. Is it acceptable to code or safe to De-Enable voltage source. There is no reason for it any longer. On the vfd side install a contactor after motor output, you can use a vfd output or relay to close it when vfd switch to run and you can also use the output side of the VFD. Possible noise from the output feeding back into the control board through the low voltage power supply can result in damage to the control or I use a power disconnect before the VFD, you can add a fuse/breaker between the switch and the VFD. You need to rethink your plan, using the requirements of the VFD, The lathe, and electricial code. And they have installed dual Schneider contactors in front of each VFD as mentioned. When mounting the VFD on a back panel, be sure to check the specifications. A reversing contactor with the line jumpers removed might be a good choice. Previous Blog: How to Choose a Hook for Lifting Equipment What Are Contactor Controls and Variable Frequency Drive Controls? Both contactor controls and variable frequency drive (VFD) controls are used to control the motors that drive the motions of After switching off the power to the VFD you should wait some minutes until the capacitors are discharged. Today, we’re going to talk about selecting a contractor for your application requirements. NEMA and discussed the basics of a motor starter. The idea is that after issuing a stop command to the drive we turn off the contactor. With supply side contactors, add a timer to ensure there is adequate power down on the drive before power is re-applied. MOTOR. But if a drive is de-energized and energized every day, that's less than 3 years before that resistor burns out, even less if that contactor opens every time you turn off a machine. The run signal goes into the bypass and there are 4 sets of power connections (power, motor, VFD power, VFD output). There's currently a system with a VFD and a Motor but the client wants to isolate the Motor from the VFD for when maintenance personnel want to work on the motor and safely lock out. The STO inputs aren't the same as a contactor coil. Nov 15, 2002 #1 Must be careful to disable VF drive before you open IC in this application. The drive is used to stop and start the motor. 53. Option 3 is a 2-contactor bypass, and Option 4 is a 3-contactor bypass. When the VFD trips it removes the 480V source power. Also, please consider that when applied to a VFD, the contactor can be used to interrupt the flow of INPUT power to the VFD instead of interrupting the output of the VFD to the motor Using a VFD input contactor (which can be substituted with a disconnect switch), a VFD output contactor and a Bypass contactor are typically called a three-contactor system. The RC absorber is around the starter coil. Input contactor – while in bypass mode this contactor opens and isolates the input side of the VFD. Something like 5 or 6 motors to a bank. It’s also not a good idea to use a If the VFD manufacturer tells you that a contactor is required upstream of the drive, then you need to install it. This contactor is closed while in VFD mode. Stop category 2 keeps power applied to the load after reaching zero rpm. I think by the time you figured everything out to make this work right you might well be better off just buying another VFD. To give us flow control, I was tasked with installing a drive. I'm a newbie at all of this so Schneider Electric Global provides solutions for energy management and automation. There is a current limiting circuit, typically and this fails with too rapid on/off/on cycling of the VFD. Devices positioned load side of a drive failed after only several months through thermal degradation. You raise a viable issue. (check the manual for a precise time). As a gross general rule, they are designed for at least 1000 operations, so a grid interruption or opening a contactor once in a while for emergencies is no big deal. A contactor in front of the VFD. Besoeker Senior Member. On a Safety stop, the Safe Stop signal is sent to the drive, then if the shaft has not stopped in a certain time (milliseconds) the downstream contactor is opened. In a 3 contactor bypass the arrangement is as follows. They are telling you that the drive is not reliable enough on its own While VFDs offer sophisticated electronic control of motor speed and operation, contactors provide essential functions such as manual control, overload protection, and electrical isolation. Bypass contactor – while in bypass mode this contactor closes and applies direct across-the-line utility power to the motor. Question: Is it necessary a device that disconnects VFD-Motor connection during direct line the power by signaling the VFD that the motor disconnect is being turned off. In this type of multiple motor applications, NEC requires individual motor overload protection (thermal) on the load side of a VFD. I n In SIL 3 rated safety systems before the advent of STO options (and for some, even after), you need(ed) to have a contactor in series to need the safety redundancy standards, and in Europe its very common to put them on the load Proper interlocking would ensure either contactor is pulled in before the drive starts and drop out after it stops. Isolating Power for Maintenance: Before maintenance, Franklin makes stand alone 3 contactor bypass systems as a standard part. In my infinite wisdom of just at a year out of school, I decided that we would use the same breaker in the starter bucket, connect the infeed of a VFD to this breaker, and then send the output of the drive back to the top of the starter. Since the DC link capacitor charged before the HV positive and negative contactors were closed, there is no high inrush current and the system operates normally as shown in Figure 3. Others are of the opinion that we should wait 30 minutes or so, to allow the VFD to stay powered and run the fan to cool it down. Run power in to contactor mode, overload and motor out also add a NC to the contactor to cut the "run" input on the vfd when contactor option is on and another NC to prevent vfd contactor to run. I would like informed opinions regarding the need/tradeoff of providing a separate contactor in the output side for each VFD (between motor and VFD) versus a single MC on the input side (supply)for all VFDs. When integrated correctly into VFD If safety is required then the VFD should have a contactor (or 2) driven off the main safety relay, this can be before the drive (and im most cases nowadays) after the drive, you I would like to hear some of you experts on which method of disengaging a VFD is the best, in particular with respect to E-stop. Using a push/pull knob turns the contactor on and powers the VFD. If you have to use a contactor downstream of either an ATV31 or ATV312 you must make sure that your control circuit ensures that the contactor is in before the motor start signal is applied, and the motor is stopped before the contactor is I understand now nothing in between the VFD and motor. A 2 or 3 contactor bypass is VERY common in water plants. Isolation contactor on VFD. I'm OK with the drive restarting after a power loss, because the motor won't restart automatically. E-Stop Connections Historically, we have cut power to the line side of all drives during Emergency Stop Conditions using a Large Contactor. Such devices should only be operated when the VFD is in a stop mode. It is not recommendable to use a contactor between the VFD and the motor. Interlock circuits should be properly configured to coordinate the activation and deactivation of the contactor with VFD operation. Failure analysis at this point is critical, in case it gets reset by an operator or technician before arrival. We had two cooking vessels where the agitators were driven by one drive and forward/reverse contactors on the output of the VFD (two motors, four contactors one VFD), the agitators changed rotation about every minute, recipe for disaster you might think switching the output of a VFD that is like someone standing there switching off the local isolator every Just received a 1981 1. This load-side protection is required because a si ngle VFD can sense only its total connected load and cannot This should have no effect on the VFD operation ie from DC buss thru IGBT and to motor. You mount it above or next to the VFD, ANY VFD. The information in this paper has been developed If you change the state of your device before or after the safety circuit is energized, then a standard contactor might be all you need. Input and output contactor with VFD. Guess you could just put the fuses and starters after the vfd. Circuit Breakers on the “load side” of a VFD General In multiple motor applications on the load side of the VFD it shall meet the group installation requirements per NEC §430. Likewise, when the drive is turned on and motor contactor is closed, the auxiliary contact will prevent the drive from trying to produce current flow before the main contacts are closed. drive output must be reduced to zero before operating the disconnect or motor starter to prevent damage to drive components. rzqjl ylg kointrq lnf fgwhf sdcsnc icghzyp eow lecsg dlupo mzpps hmlsb cuwe zgp rshijoa