Help with circuit breakers on the line side of the VFD.

[Windrunner]

Hello everyone,

I'm having trouble selecting the right circuit breakers for the "line side" of my VFD. The common advice is to check the manufacturer's recommendations. While the manual suggests specific in-house types, I'm unsure about alternatives. Also, I don't need UL certification.

My VFD is a PowerFlex4M (22F-D2P5N113 series A), and the manual recommends:

Fuse: UL Class J, RK1, T, or Type BS88; 600V (550V) or equivalent.Circuit Breakers: HMCP or Bulletin 140M, or equivalent.

I'm having difficulty finding suitable alternative parts or determining what the equivalent part might be.

Additionally, can I use an MCB instead of an MCCB or MPCB? For example, on one occasion when we used an ABB VFD, one of the options mentioned in its manual for selecting the supply disconnecting device (disconnecting means) was: a circuit breaker suitable for isolation in accordance with EN 60947-2. In that case, we simply used the following MCB (Miniature Circuit Breaker): Acti9 iC60H, 3P, 6A, B curve, 10000A (IEC/EN 60898-1), 15kA (IEC/EN 60947-2).

Or am I interpreting it incorrectly, and the option mentioned above does not pertain to the characteristics of the CB but rather to its capability to be placed in the OFF position and safely disconnect power?

Thank you.

---

 

[WhinnieThePooh]

An equivalent MPCB might be this: LINK

I would also be interested in what is considered the best option for a breaker on the line side of a VFD. Most of the VFD brands we work with specify molded case so thats what we use. However it seems as though the breaker doesn't offer much as far as protection because the VFD is far more sensitive to shorts, ground faults, etc.

Would an MCB be an acceptable option?

 

[Scottryan03]

Motor protector is discontinued, Replacement: 140MT-C3E-B40

 

[Windrunner]

Hello.
@WhinnieThePooh I'm searching for something available in the EU, possibly from Schneider Electric... but thank you anyway. I'm also curious why fuses and MCCBs are acceptable, yet MCBs are not. From what I could gather, people consider MCBs the cheapest option and not the best fit. They're typically suitable only for smaller applications; larger ones often require MCCBs.
@Scottryan03 Thank you, but I am more interested in its equivalents.

Anyway, I will probably switch to ABB VFD because this one doesn't have an STO signal. I need to think about it.

 

[BryanG]

Different manufacturers have different requirements for the protection devices, which vary by the regulations that apply where the drive will be used. ABB list fuses, or Manual Motor Starters as acceptable, Invertek allow fuses or Miniature Circuit Breakers (MCBs). If you follow the manufacturers requirements then your backside is covered in the event of a problem, if you go your own way, you take your own risk. In the EU it is far more acceptable to go your own way, so long as you can justify it. In North America you can't swap one equivalent for another, things are only allowed if they have been tested together.

 

[JesperMP]

The protection in front of the VFD is only for short circuit protection.
Overload protection is done by the VFD, and/or a motor thermistor (recommended).

You can install a protection that may not protect the VFD sufficiently against damage, but it is not unlawful. The law only says that a short circuit current shall be interrupted by the protection device. So the important things is to coordinate the current breaking capability of the protection device with the prospective short circuit current at the location.

In the past I have experienced that electronic power devices (soft starters and VFDs) were required by the manufacturers to be protected by semiconductor fuses (extra fast fuses). I don't see that any longer. I think the electronics have become much more resilient than it was in the past.

Another issue that I think belongs to the past, was that the inrush current could trip a protection device. So you would select a protection device with transformer characteristic. But now I notice that most manufacturers specify regular motor protection circuit breakers.

 

[Rob...]

MCBs are not built to the same standards as MCCBs or Fuses, and for that reason most are only rated to be used in domestic applications. This is certainly true in the EU/UK.

Generally they also have a lot lower SCCR rating than MCCBs or Fuses, this also makes them quite often unusable in industrial applications.

The MCB you list meets both standards.

 

[WhinnieThePooh]

@Windrunner, I apologize I didn't take note of your location. As for a product from Schneider Electric, we have used the GV2 series with excellent success. It is a fantastic product, virtually bulletproof.

Schneider breaker: LINK

The protection in front of the VFD is only for short circuit protection.
Overload protection is done by the VFD, and/or a motor thermistor (recommended).

Thanks for the straight answer. I now know what to tell people when they ask me

 

[lfe]

I had simply used the same protector as recommended for the motor power like it not have a VFD.

 

[Windrunner]

Hello,
because of the STO signals, I am considering using ABB VFDs. Anyway, after checking the user's and hardware manuals, I found the following recommendations: - Fuses: gG or UL Class Tor CC (600V) 10 A. - MMP Type E MS132-6.3 Input Amps: 4.1. So if I understand this correctly, I need one of these for branch circuit protection?

Besides the parts mentioned above, do I need any additional parts for protection?

Thank you everyone , for your help and answers.

 

[WhinnieThePooh]

Anyway, after checking the user's and hardware manuals

What user manuals are you referencing? The ABB?

If so, can you provide the part number of the VFD?

 

[Windrunner]

What user manuals are you referencing? The ABB?

If so, can you provide the part number of the VFD?

Hello,

I'm sorry I forgot to mention it earlier, but yes, I obtained information from the ABB ACS355's manual (link bellow) and I am considering using the recommended motor protector. The VFD I will be using is ABB 03x-02A4-4.
Manual: (page:381)

https://library.e.abb.com/public/805f31a82d524d8aa8a750011e2cd001/EN_ACS355_UM_E_A5.pdf

Any ideas about the purpose of S1-M3-25? It requires the use of the S1-M3-25 line-side feeder terminal with the manual motor protector to meet Type E self-protection class. And do I need one or two (for both input and output of the device)?

Thank you.

 

[BryanG]

The S1-M3-25 is for UL approval, for EU use you don't have to worry. And if you did need it, it is just on the input side.

 

[Windrunner]

Hello.

I have a question regarding the VFDs I plan to use. VFDs I have access to are technically oversized for the motors I intend to use, and I'm unsure if this could pose a problem.

The motor specifications are as follows: kW 0.37, V 230/400 delta/Y, A 1.82/1.05, min^-1 1385, and cosfi 0.75.

If I decide to proceed with the oversized VFDs, should I stick with the motor protector recommended by manufacturer, or would it be advisable to scale it down?

Thank you.

 

[WhinnieThePooh]

I would stick with the protector recommended by the manufacturer of the VFD.

We usually oversize our VFDs about 30% H.P. rating. You will just have to adjust the overcurrent/thermal protection of the VFD.

I believe the "Guided Setup" on the ABB drive should walk you through the parameters needed for a basic application.