We have a situation where we have a long run of cable feeding some equipment.... the cable drop has reduced the voltage to approximately 510V 3p from 600V (fed from 13800VD - 600Y/347V 1000kVA dry type transformer with a 15A NGR). The equipment is having trouble 250HP)due to the drop and we...
What would be the output voltage of an two 600-120V PT's wired in open delta (b phase grounded) assuming balanced 600V 3p source?
Would it be VAB = VCB = VCA = 120VAC or VAB = 120VAC, VCB = 120VAC, VCA = 1.73*120VAC...
Hello all,
Situation: 75kVA 600V-240/120VAC 1P solidly grounded transformer with 200A fusible disconnect c/w TRS150R fuses on the primary, and a 400A 30CCt lighting panel on the secondary. Panel has main lugs only, 3x100A branch circuits, 1x60A branch circuit, 1x15A branch circuit. Items all...
Hello All,
We have a new system that is fed from a single D-Y transformer. We are now adding an alternate source (a generator). We would like to resitance ground both sources.
The questions is can this be done with one NGR? The suggestion was made to place a zigzag with NGR in the secondary...
Hey Folks,
Does anyone know why cable lugs have a voltage rating? Bare copper bus bars do not.... and that is all a lug is?
I would assume it is for tracking distance to the insulation....
However, I am unclear as the use of 600V lugs at 15kV is common practice in industry.
Regards,
TULUM
This has been discussed in the past - but the threads are now closed.
We have many load centres (unit transformers) that have a HV switch with a dry type transformer and secondary distribution. As we are all aware the secondary transformer bus to the main breaker has a high arc flash...
Hello,
I would like to make a PCB circuit that basically is a microchip controlled switch citcuit for a 5V 5.2A purely resistive load. The switch would be activated for 10Seconds maximum and would not have to be operated again for 60secs or more (could be days actually).
Can typical PCB traces...
Just a quick questions... as a rule we purchase the right lugs for the cable (i.e 1 run of cable per phase gets a single lug, 2 runs gets a double, etc).
In the case of some of the 400A disconnects we purchased we received two hole mechanical lugs however, we installed 1 run of cable per...
Hey folks,
Does anyone have any experience or know of any articles that discuss the pros and cons of expanding (i.e buying another facility) vs. double worker shifts?
Currently our organization works 40 hour weeks 8 - 4:30 5 days a week with overtime as needed. To keep up with the workload we...
Hey folks,
We are buying a 6.9kV - 600V 2/2.6MVA air cooled dry type transformer (7% Z min). The primary will have S&C SM5 fuses and the secondary will be a Molded case breaker (rated 35kA). The transformer is delta - Wye with a 5A NGR that is alarm only not tripped.
I have charted the SM5...
Hey folks,
Simple question that I can't seemed to find a rule of thumb for...
When does it become worthwhile to use a microcontroller for a project vs. a typical electronic / TTL / CMOS circuit?
For instance if you want to make a horn circuit, or a temperature sensor is it more productive and...
Hey Folks...
I have been gone awhile... back now...
Here is a questions...
I have a proposed starter for a piece of mobile equipemnt (200HP 600V + 10kVA tz).
The starter consists of:
- 400A disconnect
- 350A J type fuses
- 350A contactor
- AB E3+ o/L
- GF Protection
- 225A outgoing cable...
Typical commercial 600V 225A, 400A, 600A splitter troughs such as BEL and Eurobec do not have withstand ratings available... yet they have CSA ratings....
What do you do when you trying to determine equipment duty under SC conditions.
Someone must have come across this before. I do not...
Does the short circuit current change at all if 3 single phase transformers are used connected in delta - wye vs. one standard 3P delta wye transformer?... assume 2.5% impedance typical...
Regards,
TULUM
The utility provided the following;
Supply Voltage: 12.48KV,
Short Circuit Data:
L-G Amps: 1869A
P-P Amps: 1782A
3P Amps: 2058A
Z1 = 1.05 +j3.34
Z0 = 1.22 +j4.39
This is on the primary of a pole top transformer that feeds one of our buildings. It is unclear yet, but I think the transformer...
Here is the situation (in canada)...
The electrcian installed a squared 600v 60a switch with a 50A fuses. The switch feeds a 45kVA (80degc) 600V-208/120 transformer. The transformer feeds a 100A 120/208v squared panel c/w a 100a main.
The electrical safety authority says that because of rule...
Hey Folks,
Anyone now of a really cheap montior for control power status?
I have a job that has ten feeders with ten separate CPT's on each feeder and the design engineer has requested that the 120VAC secondary of each CPT be monitored... this is lots of $ for something we have never done here...
Hello,
Can anyone enlighten me on how to size a zero sequence ct for a multilin 750 relay.
The manual is not real clear and it suggests a 1 to 5000A primary with a 1 or 5A secondary.
The system will be resistance grounded with a 10A NGR...does this matter? Since it is wrapped around the...
Hello,
I am from the resistance grounded world, and this is the first time I have to install a solidly grounded system. It is a 4160V-600V 650kVA transformer.
I look in table 17 of the CEC and it states that over 475 the ground conductor should be 000 at amperages over 475, is this...
Hello,
I am looking to make a small circuit that is capable of detecting 600Vac. All it would need to do is detect if the voltage was present and then turn on a dry contact.
I need it to be small, so I was thinking electronics...otherwise I would just use a PT.
Any ideas...
Regards,
TULUM
