We have been working with a new PM sync motor, which has very good speed control (can tune the speed in increments of 2 RPM up to 8 KRPM) when run open loop. ( ! ! ! ) For previous apps of ours, we have used BLDC with a resolver, but have wanted to get away from using resolvers. Our app...
Do electric motors to be used in a Class II Div II Group F or G environment require more than mere short circuit and overload protection, i.e., do they require thermistor protection also?
Our shop has 240 3 ph 60 Hz, and we need to run a short term (several 5 minute tests) on some equipment needing 480 3 ph.
We have a disconnected distribution transformer, 480 Y / 240 delta 150 A secondary, which is at least 30 times the ampacity needed for the test.
Is it OK to backfeed...
We got some inquires for rotary electric vibrators, using 42 VAC 3 phase. Anyone heard of such service? Where is this used? (We thought this inquiry was a typo, then we got a few more.)
When I saw this headline, I could not help but envision Keith explaining some contraption to the Cal Hwy Patrol.
http://www.cnn.com/video/#/video/bestoftv/2008/12/16/pn.most.outrageous.riding.couch.cnn
BK
In general, the speed of sound c is given by
c = ( C / ? ) exp 1/2
where C is a coefficient of stiffness and ? is the density.
In a solid, this stiffness is expressed as the Young's modulus.
In a solid rod (with thickness much smaller than the wavelength) the speed of sound is given...
As requested, this is a new thread, taking up the subject of: For purposes of both safety and ease of diagnosis, where is the best place to put NC contacts that deny activation of a motor contactors: 'Tween the contacts and neutral or 'tween contacts and hot feed to coil?
Below is the...
We are supplying a captive coal-burning power plant ex-proof rotary electric vibrators as material flow aids. Their req'ts are not well defined as to their need for ex-proof equipment; the impression we rec'd was that the ex-proof req'ts were being explored so they would have the option to burn...
Recently I viewed a series of acoustic spectra that clearly showed a 4.3 X speed series of peaks, with the speed varied over a 10X range (50 - 500 RPM). Rotary device was a BLDC motor/flywheel combo, riding on a pair of angular contact bearings, roughly 1.25 inches OD.
Is this a bearing...
Folks, if a 14" diameter body, rotating at 1000 - 1500 RPM, weighing about 40 pounds is balanced down into the 0.1 g - cm. range, what grade of G is that?? (Is there one?)
BK
I am trying to source two items:
- 250 HP, 4160V, 3 ph, Ex-prf motor (D1Cl2, F&G), and
- Soft starter for above (does not have to be Ex-prf).
For motors, I have found US Motors, Reliance, GE and Continental.
For Soft Starters, GE, A-B, ABB and Saftronics.
Anyone know of any others...
We are trying to source some SO or SOW cable (18 gauge, 4 conductor, 600 V, black Neoprene outer jacket, 10 mm max OD) in Europe, for products headed for the Nor Amer market. CSA approval is an issue.
Are the HO5 or HO7 RNF grades similar, a sub? Do they bear CSA approval?
Thanks for any...
Concerning 3 digit IP ratings: There seems to be some ambiguity as to the standards for the 3rd digit, which refers to mechanical impact survivability.
When trying to figure out an IP65-7 rating, the -7 rating is listed as meaning able to survive 6.0 joules of impact (1.5 Kg @ 40cm), at...
We are trying to determine which value to chose as a running cap to use with a small single phase motor. This 120 VAC motor is a rotary vibrator, used for material flow aid (packing tables), and runs roughly 30% of the time. The motor mfr. supplies a 2.5 uF cap; our customer (an OEM) specs a...
I am interested in finding some data on how common distortion due to stress relieving activity takes place during transports of pre-fab'd bridge or other large structural components. I am especially interested in structures made out of some of the newer High Performance Steels.
