Not sure if it matters, but there's some more information about the motors in the Owner's Manual that I should have included:
Traction Motor - 2400 rpm, Permanent Magnet, 2-pole
Mower Motors - 3000 rpm, Permanent Magnet, 2- pole
There are three 12V batteries in series, so these would be...
Question - Do I need to do anything special before applying power to electric motors that have not run since 1985?
I am restoring my father's John Deere Electric 90 electric riding lawn mower which was built in 1972 and has been parked in a storage shed a LONG time. It ran up to that time, but...
Yes, wind turbines. The pad-mount transformer is rated at 1850 KVA. High side is 34.5 KV with cable up to 1250 kcmil going to a 345 KV substation. Low side is 600 V with four DLO (Diesel Locomotive) cables (DLO262, I believe). So a fault at a turbine is fed not only from the substation, but...
Figured out the attachment process... Here it is. -FEinTXhttp://files.engineering.com/getfile.aspx?folder=657cb6e1-1acd-453c-ab52-e3ac77c32f3f&file=20091117230726615.pdf
Thanks for all the great input!
Yes, there are actually 2 issues that I'm looking for help with:
(1) Will the smaller CB actually see 47 KA coming across the #4 wire? If so, what happens? Will it not open? Will it explode?
(2) The arc flash incident energy for the line-side of the...
According to our arc flash study, we have a maximum of 47,000 A available 3-phase fault current coming into a 600 V cabinet via some really big copper buswork and wires. It connects to a main circuit breaker which is rated at 50,000 A. However, there are also three 4 AWG wires that tap off the...
Dave,
The pics were of a new unit--just showing how the mechanism is designed. The failed units just have the rods bent back a couple inches though.
If interested, I could post a pic of the bushing failure. These are a lot more interesting, but not really the topic I was chasing...
Rbulsara - I do not have a picture of a blown out door, but nothing very dramatic. Often, no damage at all. Worst one was bowed and had to be sent back for repairs.
We have had 6 failures (installed base is 180) where the bushing arced to the retainer plate (GND) on the high side, and yes...
DPC,
One difference between this and a 480V switchboard, PMT's are typically not behind security fences, or in mechanical rooms, or off-limits in some other way. There are smaller, lower voltage PMT's sitting in people's front yards as part of underground distribution systems. I've often seen...
Question - Is it normal for a Pad-Mount Transformer to have doors blow open when there is an internal arc flash?
Background
+ Equipment = 1.85 MVA transformer at 34.5 KV at a wind farm
+ Initial Electrical Failures - Elbow failure or Bushing failure
+ Typical Fault current 6-20 KA
+ Door...
Hello,
We are receiving a new substation at a wind farm equipped with capacitor banks. At a previous job, they used Joslyn zero voltage switches to engage the cap banks and during final testing a digital O-scope was used to confirm the timing was correct. 2 of the 6 switches had to be...
We are building a 34.5 KV collection system for a windfarm, and almost all the 3-phase cable is configured in trefoil. Occasionally, the installers make a mistake and in the middle of a circuit, one cable will jump through the other two. For example, you might have 1000' where the orientation...
I need a transformer expert...
Recently, during commissioning of a new 230 MVA 345-34.5 KV transformer we came upon an interesting problem. The LTC controller (Beckwith) was wired to monitor the low-side voltage and thus regulate it to a pre-set value, even though the LTC is built on the...
Hello,
We are building a wind farm with a 34.5 KV collection system. The contract calls for hi-pot testing prior to energization of all circuits. In addition to the hi-pot, the customer has recently decided to have the entire collection system tested by a reputable firm using Partial...
Matwong,
Thanks for the post.
The cable size is 1250 kcmil laid in a flat configuration (7.5" center-to-center). This is the largest cable used at the site, and I don't know if this cable is available in a larger size.
-FEinTX
I'm hoping there's a cross-bonding expert out there...
We have a 34.5 kV underground circuit 9600' long. Our EPC is transposing the cables and cross-bonding the neutrals every 1600' (6 total sections), except at the mid-point, they neither transpose or crossbond (a straight-thru splice)...
I posted earlier this week about sheath testing on a 34.5 kV collection system and with the information I got here coupled with some information from the cable supplier, I now know why our EPC is failing these tests. Basically, (1) they were testing the sheath at too high of a voltage level (10...
