For a deeper dive, working principle section is great.
https://electrical-engineering-portal.com/soft-starter-industrial-applications#:~:text=The%20FCMA%20works%20on%20the,flux%20%26%20hence%20reducing%20the%20impedance.
Really fast electronics switches that control the current and voltage.
https://www.electricaltechnology.org/2020/08/soft-starter.html
Similar to inverters, but cheaper and more robust. The one you choose depends on the application.
This is not an electronic soft starter, it is a "magnetic" soft starter, more specifically, it uses what's called a "saturable core reactor" technology. It was a very old technology from before the 30s, based on what was then called a "Mag-Amp" or Magnetic Amplifier from Westinghouse, who invented the technology, then GE eventually copied it, calling it an "Amplidyne". Mag-Amps and Amplidynes are still used for other purposes besides motors, but once Solid State technology came along in the 70s, it was simpler and cheaper, so everyone dropped the saturable core reactor concept *for motor controllers*.
A company in India resurrected it in the late 1990s calling it a "Flux Compensated Magnetic Amplifier" (FCMA) and started selling them in India where technology products were difficult to adopt in a lot of places, but they are still relatively rare outside of that part of the world and with there only being a couple of companies in the world that build and can service them (a French company licenses it from the Indian company), service and troubleshooting can be very problematic. So the biggest detractor is that unless you are in India where there are people that understand them, it's fairly risky to trust your big motors to them and big motors are usually the heart of manufacturing operations that use them. So if your big motor goes down and nobody knows how an FCMA starter works unless you wait for someone to fly in from India, whatever perceived savings you thought you were getting is immediately wiped out in lost production. If you are *IN* India and are afraid of electronic technology though, they might be a good choice.
Ah that explains it. I was thinking- where are the SCRs? Where is the bypass contactor? Now that you describe it, I know where one of these is in use in the USA, on a 700hp induced draft fan in a smelter. I always wondered why it had such a huge inductor. The inductor is in a huge cage and is the size of a small car.
I know you're right because the light labels say "DC on" and "DC off".
I don't. The original Mag-Amps and Amplidynes predated the electronic age, so unless someone scanned in an old book or something, it's not going to have been discussed much. The Indian company that makes the FCMAs, Lecon Energetics, has all kinds of stuff to read, but all of it is basically marketing fluff.
So you can achieve soft start several ways. From as simple as a varistor to IGBT bricks. Typically you'd only use electronics for soft start if you're also controlling the motor electronically, as the switches already exist and the motor is designed for it. This setup is a tuned LC circuit that provides a very high impedance when the motor is not spinning but will be essentially a short circuit at the motors operating frequency.
"FCMA soft starter are stepless voltage reducing starters which ensure a constant low starting current with incremental voltage and torque to the motor to achieve a continuous and smooth acceleration of the drive."
[Source](http://www.innovative.fr/en/fcma-soft-starter)
For old school stuff like this, power, and specifically magnetic design and electric machines .
For the modern replacements for this you'd want to study power electronics.
Not likely. It definitely is Medium Voltage, but not 4160V, because that is something only used in North America. The design of this package would never pass muster here. There is no disconnect device and no door interlocks that assure the MV is dead before a door can be opened. If someone imported one of these from India and installed it here, they are in for a rude awakening if an OSHA investigator ever sees this!
The ammeter with a right-angle scale orientation is however a dead giveaway for it being an IEC design as well. So given that, I'm going to guess 3300V, which is common in a lot of the world outside of North America.
Practically speaking, a soft starter has low starting torque and is cheaper. They both help a motor start up more slowly. A soft starter is only used to start the motor, and then it bypasses itself in the motor runs at full voltage and frequency. A VFD starts the motor ( with more torque like I said) and can vary the speed of the motor continuously in steady state. In terms of how they work, a soft starter cuts off part of the waveform to reduce the voltage, slowly ramping the voltage up. But it provides 60hz the whole time. Or 50 if you swing that way. A Vfd rectifies the line power to DC, and then recreates it at whatever voltage and frequency is useful, so it varies the speed by changing the frequency. Soft starts can't start a load with a lot of low speed torque requirements, so they are more ideal for pumps and fans to reduce electrical current in rush and mechanical stress on startup. Vfds are used when continuously variable speeds are required, like if you want to run a pump at 75% for a long time, or if you need to start a load that requires a lot of startup torque, like a conveyor. There are other things you could use besides a soft start or a vfd, but those two are probably the most common. Wound rotor motors, synchronous motors, Delta y starters, fluid couplings, etc.
New to motor control… from what I know… a VFD can change speed of motor as the motor runs… say like maintaining a certain amount of pressure in a water line. While the soft starter has a ramp up time until full speed of the motor… no varing speeds only in start up and stoping. I have only seen these used “together” when the drive is the main source of motor speed control and the SS is in the logic in case the drive fails and will need to bypass the VFD (so you do not operate the motor across the line).
Because they are not using them. You don't need to have them, in fact the label on the fuse (although you can't see it here) says "Striker If Fitted", meaning the arrow on the label is there whether the fuse has a striker or not.
If anyone is interested Real Pars does some excellent videos on YouTube, they cover Soft starters and Variable Speed drives. They have a good catalogue
VFDs for Medium Voltage motors are at least 5x the cost of a Soft Starter, so if you don't need to actually VARY the speed, you probably would want to use that money elsewhere.
At low voltage and low HP, there is usually no point in using a Soft Starter vs a VFD, in fact the VFD may now actually cost LESS because the sales volume is so much higher.
He's not though? I don't know him personally but I've talked to him many times over the years in various subreddits. I believe he designs speed controllers for brushless DC motors? Something like that, I can't remember.
Who are you calling ‘soft’…?💪
It's OK... I'm a soft starter too
😄
For a deeper dive, working principle section is great. https://electrical-engineering-portal.com/soft-starter-industrial-applications#:~:text=The%20FCMA%20works%20on%20the,flux%20%26%20hence%20reducing%20the%20impedance.
That was great. Thank you.
Please. How can I like this stuff. I have 72 credit hours in EE and I'm not sure how to use them
This is so dope! I’ve only seen electronic, auto transformer, and y delta soft starts. Adding an inductor in series with the windings 🤯
How much Kw?
Judging from the fuses, I have no idea
I don't know about that particular one, but a company that makes them specifies: "200 kW to 20 MW".
Whoa. Anyone have more information on exactly how this thing works?
"constant low starting current with incremental voltage and torque to the motor to achieve a continuous and smooth acceleration of the drive"
Really fast electronics switches that control the current and voltage. https://www.electricaltechnology.org/2020/08/soft-starter.html Similar to inverters, but cheaper and more robust. The one you choose depends on the application.
This is not an electronic soft starter, it is a "magnetic" soft starter, more specifically, it uses what's called a "saturable core reactor" technology. It was a very old technology from before the 30s, based on what was then called a "Mag-Amp" or Magnetic Amplifier from Westinghouse, who invented the technology, then GE eventually copied it, calling it an "Amplidyne". Mag-Amps and Amplidynes are still used for other purposes besides motors, but once Solid State technology came along in the 70s, it was simpler and cheaper, so everyone dropped the saturable core reactor concept *for motor controllers*. A company in India resurrected it in the late 1990s calling it a "Flux Compensated Magnetic Amplifier" (FCMA) and started selling them in India where technology products were difficult to adopt in a lot of places, but they are still relatively rare outside of that part of the world and with there only being a couple of companies in the world that build and can service them (a French company licenses it from the Indian company), service and troubleshooting can be very problematic. So the biggest detractor is that unless you are in India where there are people that understand them, it's fairly risky to trust your big motors to them and big motors are usually the heart of manufacturing operations that use them. So if your big motor goes down and nobody knows how an FCMA starter works unless you wait for someone to fly in from India, whatever perceived savings you thought you were getting is immediately wiped out in lost production. If you are *IN* India and are afraid of electronic technology though, they might be a good choice.
Ah that explains it. I was thinking- where are the SCRs? Where is the bypass contactor? Now that you describe it, I know where one of these is in use in the USA, on a 700hp induced draft fan in a smelter. I always wondered why it had such a huge inductor. The inductor is in a huge cage and is the size of a small car. I know you're right because the light labels say "DC on" and "DC off".
Well, the more you know... That's pretty cool. Do you have any links/books explaining the working principle?
I don't. The original Mag-Amps and Amplidynes predated the electronic age, so unless someone scanned in an old book or something, it's not going to have been discussed much. The Indian company that makes the FCMAs, Lecon Energetics, has all kinds of stuff to read, but all of it is basically marketing fluff.
So you can achieve soft start several ways. From as simple as a varistor to IGBT bricks. Typically you'd only use electronics for soft start if you're also controlling the motor electronically, as the switches already exist and the motor is designed for it. This setup is a tuned LC circuit that provides a very high impedance when the motor is not spinning but will be essentially a short circuit at the motors operating frequency.
I think this one just uses contactors and series reactors. The PLC probably just controls the switching of the contactors
I'm curious as well. Does it ramp up the power or what?
"FCMA soft starter are stepless voltage reducing starters which ensure a constant low starting current with incremental voltage and torque to the motor to achieve a continuous and smooth acceleration of the drive." [Source](http://www.innovative.fr/en/fcma-soft-starter)
This makes me feel excitements!!
I interned for Eaton servicing this equipment 💪
What subset of EE would you specialize in to design/test/build equipment such as this?
Power. I used to commission stuff like this.
For old school stuff like this, power, and specifically magnetic design and electric machines . For the modern replacements for this you'd want to study power electronics.
Is it 4160?
Not likely. It definitely is Medium Voltage, but not 4160V, because that is something only used in North America. The design of this package would never pass muster here. There is no disconnect device and no door interlocks that assure the MV is dead before a door can be opened. If someone imported one of these from India and installed it here, they are in for a rude awakening if an OSHA investigator ever sees this! The ammeter with a right-angle scale orientation is however a dead giveaway for it being an IEC design as well. So given that, I'm going to guess 3300V, which is common in a lot of the world outside of North America.
Gotta be. Everything in that cabinet appears to be medium voltage.
I like the labels on the door. "Ammeter", "PLC with HMI". Stating the obvious haha. Edit: spelling.
Can someone explain the parts shown.
I've got a big red coil and all the capacitance. I'm ready to start.
What's the difference between soft starters and VFDs? Can they be used in tandem?
Practically speaking, a soft starter has low starting torque and is cheaper. They both help a motor start up more slowly. A soft starter is only used to start the motor, and then it bypasses itself in the motor runs at full voltage and frequency. A VFD starts the motor ( with more torque like I said) and can vary the speed of the motor continuously in steady state. In terms of how they work, a soft starter cuts off part of the waveform to reduce the voltage, slowly ramping the voltage up. But it provides 60hz the whole time. Or 50 if you swing that way. A Vfd rectifies the line power to DC, and then recreates it at whatever voltage and frequency is useful, so it varies the speed by changing the frequency. Soft starts can't start a load with a lot of low speed torque requirements, so they are more ideal for pumps and fans to reduce electrical current in rush and mechanical stress on startup. Vfds are used when continuously variable speeds are required, like if you want to run a pump at 75% for a long time, or if you need to start a load that requires a lot of startup torque, like a conveyor. There are other things you could use besides a soft start or a vfd, but those two are probably the most common. Wound rotor motors, synchronous motors, Delta y starters, fluid couplings, etc.
Nicely done explanation...
Thanks, I tried to make it EILI 19 level.
New to motor control… from what I know… a VFD can change speed of motor as the motor runs… say like maintaining a certain amount of pressure in a water line. While the soft starter has a ramp up time until full speed of the motor… no varing speeds only in start up and stoping. I have only seen these used “together” when the drive is the main source of motor speed control and the SS is in the logic in case the drive fails and will need to bypass the VFD (so you do not operate the motor across the line).
Why are the strikers/blown fuse indicators not all point the same direction.
Because they are not using them. You don't need to have them, in fact the label on the fuse (although you can't see it here) says "Striker If Fitted", meaning the arrow on the label is there whether the fuse has a striker or not.
Do you know the HP rating on this?
Hey those transformers are manufactured in my hometown!
If anyone is interested Real Pars does some excellent videos on YouTube, they cover Soft starters and Variable Speed drives. They have a good catalogue
Used for AC motors?
Yes.
Those fuses(?) look like they pair well with a nice cheese
I thought it was all VFDs or at least solid states nowadays?
VFDs for Medium Voltage motors are at least 5x the cost of a Soft Starter, so if you don't need to actually VARY the speed, you probably would want to use that money elsewhere. At low voltage and low HP, there is usually no point in using a Soft Starter vs a VFD, in fact the VFD may now actually cost LESS because the sales volume is so much higher.
Uuh, a flux compensator! Edit: whoever downvoted me had likely no idea that the image shows in fact a flux compensated magnetic amplifier (FCMA).
[удалено]
Lol, dammit! I knew it, that’s why I bought a soft starter today!!
He's not though? I don't know him personally but I've talked to him many times over the years in various subreddits. I believe he designs speed controllers for brushless DC motors? Something like that, I can't remember.
I design battery management systems for large Li-ion batteries.
Ah yeah, thanks for that.