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Forum Index : Microcontroller and PC projects : Variable Frequency Drive (VFD)

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PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1139
Posted: 01:05pm 14 Apr 2025
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Just an FYI:

I noticed that VFDs are insanely inexpensive on AE and so I grabbed a 2.2KW unit to play with. Hooked it up to an old Bridgeport knee-mill spindle-motor and I am totally impressed.
So many possibilities with these devices. They also have a flux-vector mode and so I think I'll grab another one and mount an incremental encoder on the motor-shaft to see how the PicoMite can perform at closed-loop position control. This was <£50 delivered.
 
Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 4854
Posted: 06:24pm 14 Apr 2025
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@Phenix,

I have no idea what you ordered, but the few that had pictures from the internals make me believe these cheap VFD's do not have a power factor controller at their input. The inputs are simply: bridge rectifier, big capacitors. Output : 3 phase bridge discretely build on large heatsink.

That may work, but in Europe is illegal. Again, your mileage may vary, but be aware that you may not be legal to install at a customer. If you have a power meter, it will have an option to show the power factor.
It should minimal be >95% at high load. A good design is 99% power factor.
When there are no power factor correction circuits inside the VFD, the power factor will be 60%...80% depending the load. Which is illegal.

Regards,

Volhout
PicomiteVGA PETSCII ROBOTS
 
PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1139
Posted: 07:16pm 14 Apr 2025
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Hi Harm, don't know yet. They are CE marked but that's self certification.

There's a guy on YouTube who dismantled one, expecting to find a mess but he soon became impressed with the build quality.

However, considering my idea, I would not be afraid of defending myself, legally.

A low PF is not good But there is no-end of process machinery where the actual duty cycle is very low but they have hydraulic pumps running constantly. Even with a poor PF, the energy consumption can be greatly reduced. Furthermore there's the safety factor. I have dealt with jurisdictions where even when making a small tooling adjustment, 100% of energy must be removed from the machine. Blocking valves on the hydraulics are not enough because the pump is still capable of oil flow and therefore creating movement.
With a VFD powdered hydraulic pump, the motor speed can be decelerated to zero RPM in between working cycles.

I will learn more tomorrow 👍😎
 
PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1139
Posted: 01:46am 15 Apr 2025
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This is all I could find:

  Quote  

In Europe, there is no single legal mandate that applies uniformly across all member states regarding minimum power factor requirements for industrial machinery. However, the European Union has established various directives and regulations aimed at improving energy efficiency and reducing energy consumption, which can indirectly influence power factor considerations.

For example, the EU's Ecodesign Directive sets requirements for energy-using products, which may include efficiency standards that could relate to power factor. Additionally, some countries within the EU may have their own regulations or standards that set minimum power factor requirements for industrial users, often in line with national energy efficiency goals.

It's important for businesses to be aware of both EU regulations and local laws, as well as any contractual obligations with electricity suppliers, which may impose penalties for low power factor. Consulting with local energy authorities or industry associations can provide more specific guidance based on the country and sector in question.



A very common piece of equipment is a Tube-End-Former which can be doing work for < 10 seconds of each minute but its hydraulic system runs throughout the shift.
Edited 2025-04-15 11:52 by PhenixRising
 
PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1139
Posted: 06:46am 15 Apr 2025
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I just found this in the manual but no explanation of how to use it. I have sent them a message.
 
PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1139
Posted: 06:56am 15 Apr 2025
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LANDRIVE CW100




I also went with the remote controller
 
lizby
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Joined: 17/05/2016
Location: United States
Posts: 3309
Posted: 01:09pm 15 Apr 2025
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What does "Danger 5 min" (below the screen and control buttons) mean or refer to?

(This stuff is beyond any use I will ever have, but I do like seeing it explored.)
PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed
 
PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1139
Posted: 01:20pm 15 Apr 2025
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Hi Harm,

Glad you brought-up the Power Factor thing  

So the item in the table is an actual monitor and I'm seeing 78° lag

Power Factor = cos(78°) ≈0.2079

Bit horrified at this but I checked typical Power Factors for DOL (direct-on-line) induction motors:



My tests are also "no load" as I can't test under-load just yet.

Source
 
mab1
Senior Member

Joined: 10/02/2015
Location: United Kingdom
Posts: 238
Posted: 05:37pm 15 Apr 2025
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  lizby said  What does "Danger 5 min" (below the screen and control buttons) mean or refer to?

(This stuff is beyond any use I will ever have, but I do like seeing it explored.)


I think it means it contains hazardous voltages for 5mins after power off?
 
PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
Posts: 1139
Posted: 02:34am 16 Apr 2025
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  mab1 said  
  lizby said  What does "Danger 5 min" (below the screen and control buttons) mean or refer to?

(This stuff is beyond any use I will ever have, but I do like seeing it explored.)


I think it means it contains hazardous voltages for 5mins after power off?


Yeah, capacitors  

This stuff is FUN. Three phase motors can be found everywhere. Dead equipment that hasn't yet been scrapped.
But now we have serious power that is controllable for <$50. Either standalone or digital/analog I/O or via Modbus.

I heard that the easiest way to obtain government funding is to come up with something related to fighting "climate change". Well this is a no-brainer and instantly proves to be effective when it comes to reducing power consumption.

I am currently in a small manufacturing company that has at least a dozen pieces of hydraulically powered equipment, running but not doing work.

I'm always the last to leave and I take a walk around the plant, switching this sh@t off. Incredible. The employees are not paying these bills so they don't care.
Edited 2025-04-16 17:22 by PhenixRising
 
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