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In USA per NEC (National Electric Code) definition: Tap conductor is Conductor with an upstream overcurrent protection whose rating exceeds the maximum ampacity of the conductor. NEC has some rules that limit length and ampacity of tap conductors. Are Tap Conductor rules unique to NEC or there...

I think overload to 115% is to address dynamic of rotational load during acceleration or deceleration, when in addition to static load there is load from inertia which needs to be overcome. PaulBr.

Thank you all for the info. Something to study. PaulBr.

Is VFD cable requiring special compression lugs? In our application we are using 500 MCM VFD cable, Lutze A2205003. Link We intended to use compression lugs 500 MCM compression lugs, Punduit LCA500-1-6 with this cable: Link However, when conductor is stripped from isolation fine strands...

Couple years ago we have built machine for Saudi Arabia. It was 3 phase 380V, 60Hz. PaulBr

I apologize for not being clear. I was using terminology that our customer was using. By assisted start they mean use of a) delta - wye contactor arrangement; b)soft start; or c)VFD. Motor in question is 3 phase, 50Hz,400VAC, 45kW motor. Customer is located not in EU but is trying to follow IEC...

Hello guy: Does anyone know answer to question in subject line? If it is indeed requirement, can relevant documents to be sited? Motor in question is regular 3 phase squirrel cage induction motor. If this is just good practice in IEC world, then when (motor size) it needs to be used? Best...

Hoxton, Thank you very much for taking second look and for the pointing to relevant standards. Regards, PaulBr

The matter of fact this is not the first machine, but second one. Consultant was hired for the first machine. That machine was very similar but slightly smaller that current one we building. His rationale do not have EMC test was that all devices have own DoC with EMC declarations in it. During...

Hoxton, Thank you very much for the input and posted attachment. We will study it. A little bit of background: We are original equipment manufacturer located in US. We are building large piece of machinery (consisting of 40 VFD motor circuits, PLC, etc.) which will go to France. These machines...

Thank you for reply. I am still not completely convinced. VFD manufacturer is stating in user manual that if its product connected according to the provided instructions it will meet EMC requirements. It implies that this manufacturer conducted testing, where input power was connected to drive...

Hello fellows: How this standard, 61000-6-2 Electromagnetic Compatibility (EMC), is applied to industrial machinery. Words in standard are saying that it is applicable to "electrical and electronic apparatus". In our case industrial machine consists of several devices (apparatuses), like VFDs...

Does anyone has recommendations how to connect imperial size conduits to metric sizes openings in motor terminal boxes. Machine is being built in China. All motor equipment is using IEC motors with metric size openings terminal boxes. However all conduits and fitting required to be PVC coated...

Jraef, I've actually noticed it with PowerFlex 525. Frame D and E of 380-460V all have output current higher than input current. PaulBr.

We have started using new families of Rockwell Automation drives, PowerFlex 525 and Powerflex 753. In the drives manual there is chart that showing drives input current rating and output current rating. On these charts output current rating is greater than input current rating. It is opposite...

You may check on these switches: http://www.hubbell-wiring.com/press/pdfs/H5184.pdf page 11. PaulBr.

I was on vacation and could not verify and respond earlier. It is centrifugial pump.

This is new installation. Because this is pump I decided to configure drive in V/Hz mode. Actually we have tried to change ramp time in both direction. Default time is 10 seconds. We have tried in both direction - 3 seconds and 60 seconds. Result was the same, drive was stack at 15-17Hz speed at...

Thank you. Now it make sense. PaulBr.

We have pump driven by 37kW motor, which is controlled by PowerFlex 70 drive. When drive is configured as scalar, V/Hz mode, motor cannot run faster than 15-17Hz. Drive is displaying about 67-69Amp and going in current limit mode protecting motor. When drive is configured as sensorless vector...