Search results for query: *

Skogsgurra, If I may share a bad experience that I once had about connecting 2 DC motors (900 hp each). Since the connection box was not so big, all power cables where pushed very close to eachother inside the connection box. To prevent friction damage between two cables or bewteen cables and...

Maybe you should consider the use of a "hi-fog" sprinkler system. This is a high pressure sprinkler system that does not flood the entire room with water but it creates a tight water mist. With a few liters of water under high pressure, you can put out a fire in no time. Even electrical...

Have you tried measuring resistance between all phases? I don't mean the resistance of each phase (to check for open windings) but there might be a problem between two phases. Make sure that you remove the starpoint connections when doing so. Kind regards

Peprl & Fusch (German) has a good solution for this problem: http://www.pepperl-fuchs.com/global/en/13577.htm This is a slip monitoring relay that uses normal inductive sensors to detect slip. This relay has alot of parameters that can be changed to make sure that it meets your requirements...

Thanks for your response, Pete. I just wasn't sure if it could reduce life of the winding insulation. Kind regards

When a squirrel cage motor is used at locations with high humidity (outside or maritime environment), most of them have a standstill heater inside. However I've seen motors without a built-in standstill heating but they where heated by automatically applying 24V to 2 phases when the motor is...

Some Ormazabal breakers have to be charged by pulling the switching lever counter clockwise first. This action is needed to charge the springs and allow it to open in case of a trip. Then the breaker can be closed by turning the switching lever clockwise and counter clockwise to open. On those...

- Is there any loss of output power? - Is the excitation current within limits? - Is the generator still producing or is it completely out? - What happens when you let the rotor spin without producing (without excitation for example?) at the same rpm as when the vibrations occur? Do you still...

Is the rotor balanced properly? Is the generator connected straight to the grid or is it being rectified & inverted first? Do the vibrations occur also when you pitch in the blades without generating power?

Thank you, Petronila So what I understand out of this document is that the out-of-roundness tolerance is depening on the peripheral speed of the commutator (wich makes sense). What I don't understand from this document is that the commutator surface should be as smooth as possible. Because in...

Found already some more info on the out-of-roundness requirements: http://www.ingenieurparadies.de/sixcms/media.php/1466/out-of-roundness.pdf

- Is there a rule of thumb for the ideal roughness of a commutator surface for DC-machines? I've found an explanation that was really helpful and they indicate ideal values (Ra 0,8 - 1,2 and Rz 5-8µm) My question: Isn't this value depending by the size of the commutator? Is the ideal roughness...

Yes, in my case the gyro found it's original heading without adjustment. I believe it was also a standard 22 type. I've read in the manual that the time to resettle is depending on the sea state (movement of the ship). When I was in this situation, I was asked by an Anschutz engineer to cut...

The quick settling function works faster if the ship was berthed when the power loss occurred (because it uses the last known heading). I've had the same problem while at sea and it took about 1 hour before the heading was restored up to an accuracy of maybe +/- 5 degrees and I think after 2...

Thank you Gunnar & Waross for your reactions. When we were adjusting the neutral point of a DC-machine we did not succeed to get the voltage to zero (think arround 100mV) but we adjusted it as close as possible to zero. Is this acceptable or do we absolutely need 0mV. This was a Indar 900hp...

I've learned from a senior electrician how to set a neutral point for a DC-motor. Later, I heard from another technician that this method is not so accurate and therefore I would like ask if this method is correct. 1) Isolate the brushes from the commutator by inserting insulation paper between...

Is there an easy way to calculate the effective charge of a battery? For example a 7,2 Ah UPS battery. When I connect a resistor, is the voltage drop an indicator of the charge level or do I need the voltage drop rate in function of time? Is there a formula to calculate this? Thanks

Waross, Thank you for your post, this was the answer to my questions. Kind regards, WV

So I assume this is a "self-excited" motor that is shown on the website, right? But the diagram that is in attachement of my original post, has a series, a shunt and 2 other field windings. Where are those 2 field windings located then? Is this also located on the poles? I'm really confused...

Thanks Waross for your reply. So the shunt and series windings are wound on the same poles? It it true that the series windings are very thick wires and with very few turns and the shunt have alot of turns but a small diameter? Where are the field windings located? Does anybody have pictures...