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Phil Dryburgh: Sorry, I picked up quantity as Hp. What are Hp's? Ignore my C) response until Hp is known. Phil Corso, PE

Hello again, Phil 1) Measure surface temp of junction box, and motor's endbells. If j/b is higher than endbells by more than 2 deg C, then connections are suspect. 2) Measure phase currents and obtain average. If individual phase is higher than average by 2%, then connections are suspect...

Since this thread has been identified as an "ENGR" problem, and you are sure that vibration is the cause, then substitute alternate-action HS devices, i.e., Push (alt pull) to Trip and Pull (alt push) to Reset. Additional concerns: make sure that contacts are suitable for the applied current...

In response to Karthik's query, following is an overview, some of which was excerpted from the consultant listed below: Pulsation Frequency is a manifestation of burner instability in virtually any combustion process. It is a thermoacoustic phenomenon resulting from inadequate "mixing" of...

In my 4-May-00, 2:53pm response on the subject, I provided an "aside"... a bit of trivia about the Moon. It revealed that due to "perturbation" we earthlings can see 53% of Moon's surface. I erred. Actually, we see about 59%. This observation is due to a phenomenon called "Lunar...

Re: George Kaufman's 4-May, 5:05 pm response, I disagree. Technically Speaking (borrowing IEEE Spectrum jargon) "compliance" in the context of this thread means "to yield," while "stiffness" connotates "to resist." Hence, the reciprocal relationship. Re: Ken Brown's 3-May, 3:36 pm...

Ken, I'm not questioning your expertise. I am aware (see "aside below) of the impact that the factors you list have on performance. As I understand it, "stiffness" is that mechanical characteristic of a translational motion system to resist an inherent weakness in the strength of an element...

Responding to Ken Brown's reply on the subject, I pose the following: I do not profess to be expert on servo's. Also, the electrical rotational problems I've experienced were generally void of feedback concerns and at least two orders of magnitude in size greater than those likely to...

In response to Simon Martin's reply no the subject: I believe that your perception of the role played by inertia in a dynamic analysis is in error. Consider the case of a motor accelerating a load (including auxiliaries) from an initial speed, N(i), to a final speed, N(f). Then the time...

In response to Wlady's query on the subject. I don't know if the following definition will point you in the right direction, but it's a start: "Game theory has brought into economics an uncertainty principle similar to the one brought into physics by the quantum theory" It came from the...

Responding to Ravi's query related to doubling frequency. From a pratical standpoint, the motor's impedance will double. Hence, without increasing voltage too, it is very unlikely that the motor will develop any useful torque. Regards, Phil Corso, PE Trip-A-larm Corp

In response to Guy Looney's query, hopefully I can reply in general terms which do not cover a specific application, nor motor size: Steady-State Operation As you already know inertia or moment of inertia or ratio, are not required for normal operating speed, i.e., the torque supplied by the...

Even though the communication link is shielded pair (single or multiple-pair), and presumably effectively grounded at only one point to a ground bus, the cable sheath/jacket may not be physically intact. Sheath/jacket could have been damaged when pulled through conduit raceway. Thus...

Responding To Guy Looney's comment: Current also changes inversely w/ voltage. Therefore, the more Technically Correct parameter to use is Power, P=SQRT(3)xVxIxPF. Regards, Phil Corso, PE Trip-A-Larm Corp

Further to my earlier reply to Vega M. Hernan's query: I also remember a very detailed, but fascinating, mathematical analysis of the ball & ore movement thru the mill and its impact on the drive motor and power transmission train (motor, gearbox, drive shaft). It was presented in a monthly...

In response to Vega M. Herman's query. Although you are looking for an electronic method, the folllowing may be useful: Many, many, years ago while working in a gypsum plant, I remember that tube mill crushing plant operators would listen to noise emissions via a block of wood held...

CAUTION: When comparing different SIS, then I recommend that you not rely on just MTBF (Mean-Time-Before-Flare, for those in HPI plants). This value can be very misleading when used without determining the Overall Integrity Factor. This is a measure of Reliability and Security capability...