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Hi, I didn´t know the Cowern Papers, it is a remarkable reference with interesting historic perspective. Induction motors selected in the comparison are general purpouse, so I assume curve B is a good assumption. Reviewing again, I see that most of non IM in the comparison, seems to have a...

Hi everybody, I took some time to compare some motor series catalogs from ABB, Leroy Somer and WEG (see link below), so to gain some insight in present days industrial grade motors, comparing motor type and size vs nominal ratings. In efficiency you can find IE4 options of any type, for IE5 it...

Hi everybody, This is question both related to a job retrofit issue, but also for hobby project applications for reusing old cores from PCBs, old appliances etc., I want to better understand how to reuse an iron core for inductor rewinding and application with different AC input voltages...

Hi, Searching for info on the BMWi3 drive I run into this report, I thought that could be of interest to share...

We have an independent analysis that confirms hypothesis of false brinelling. The point is that we have not ever blocked longitudinally the motors once assemmbled to transmission gear,etc., and we can not trace clearly if the problem occured while transport of the assembly, or while the...

I will come back if I got more detailed info. The issue is FALSE brinelling, allegedly caused by vibration in transport, and the supplier tells us locking for transport, but refers specially about longitudinal locking. We have 2 screws for that in the NDE. Mr. Englud, I would appreciate if you...

Hi everybody, We have had a requirement from a motor supplier (induction, 200kW range), about the need of inmobilising the rotor in longitudinal direction, to avoid brinelling problems in the bearings. This is to apply once the motor is mounted on the machinery we build. We have had lots of...

I will try to be more detailed. Let´s see... We have 3d models for both ducting with all details, outlets etc. for "branch A" and "Branch B". It has been done a CFD calculation with two defined flow inputs for each branch. So we have two points of the (Inlet Pressure-Inlet Flow) curve for each...

Thanks for the reply. Our supplier have done CFDs calculation for "branch A" and "branch B", so to get the system curve for each flow path. Then they have done a calculation of the fan outlet T section, usign as outlet conditions the system curve for each branch. They have done then the...

As I don´t see a lot of activity in the ventilation forum, I would ask if someone can make some comments/suggestions to the following thread, thanks in anycase thread1043-416400

Seeing Tesla S Drive, and after the discussion seems, as you have well explained, that the Model S motor is a Tailor made solution with a high freq. motor and special cooling. If you see the video, the inverter design is also quite remarkable and compact, sharing the water cooling with the...

Thanks, got it. Two additional doubts. 1. If motor is designed for a higher freq. Its power/weight ratio will be higher. Why is that not generally used in vfd Motors. I.e. with higher pole count to keep speed, or even with a reduction gear. 2. Comparing with given example, 44kW 50hz...

In the given examples the "regular" industrial motors of ABB, EMOD, VEM, are all 4-pole motors of 1500rpms synchronous speed. The "special" WEG and Tesla motors declare 4000rpms the first, and can be calculated 5800rpms the second (to match 270kW power). That gives for Tesla about 193Hz of...

Hi, after seeing a video of Tesla Model S drive and some impressive specs I have done a little of investigation in currently in production water cooled induction motors. I took 250kW 4pole as reference for comparison, and found the following typical specs for some motor builder datasheets...

Hi everybody, We are working in a system with an HVAC duct with two outlets, something like in this sketch Our consultancy uses a model applying the following BC: set the inlet flow fixed, and P=0 at the front surface of the plate holes and slots (almost aligned with the duct wall). I don´t...

Hi, I am looking for info regarding regular service routes with high grades (>3.5%) in adhesion type railways, and brake types & solutions associated with them. i.e. this link in wikipedia Link I see several regular service lines in switzerland, the Docklands Lightrail in London and a HSL in...

I traced back the defined component and it says one of these: SK3/16 P600S DA6 1600 The first I checked and it is for 1,8A avg, that should be enough for the regular load. Anyway the fact only a small number of them have failed and, as presently known, always in open circuit (we will check...

Hi, We have had some faults (last year like 3 in total 60 equipment) due to a diode failing in open circuit. It is on top of a DC control circuit just after the MCB, and has the function of avoiding reverse supply to upstream circuits. The diode is 3A RMS and after checking we have seen some...

Nop IR, real application from DC 750V transport network. i asked the supplier and got this: We have on the input side a boost converter, this is not resonant switched. We generate from that a voltage intermediate circuit. At this intermediate circuit is connected a Series resonant converter...

Hi, I have a doubt regarding isolated resonant DC/DC topologies. I understood that for keeping the resonant mode the input and output converters shall be in some way synchronised. With the attached block diagram from a Auxiliary DC PS supplier, how do you get that with a rectifier in between...