I have following additional opinion for your consideration.
1. If 900 A is FLA x 1.25; that is you had taken "the code in many places and good practice to limit maximum continuous loading to 80% of the maximum ampacity". Attention: The size may base on 900 A. Do NOT derate further by 0.8 factor...
I have the following opinion for your consideration.
1. In most cases, busbars are of short length say < 30 m. As their resistance and reactance are very low, therefore the voltage drop is of NO significance. For your case 2.5 m (10'); ignore it.
2. For installations in the US, take the UL...
I have the following opinion for your consideration.
1. Transmitter is about 200 m would affect the accuracy. It is affected by besides the voltage drop, more importantly is by the electromagnetic interferences; switching and motor etc.
Suggestion: Relocate the transmitter (which is of very...
I may had misunderstood your question.
1. I had fabricated thousands of LV withdrawable system. It is standard design/practice that no (test supply) disconnections are required when the unit is to be put into the test position.
In test position:
a) the main power contacts shall be disconnected...
1. Do you mean maximum or minimum?
2. What I understand the standard organizations are involved with the safety, on use of electricity and equipment i.e. motors, switchgear, and UPS systems etc., but not on the lifespan or recommended operational lifetime.
Che Kuan Yau (Singapore)
@ Mr FilipRST (Electrical)
I notice some unusual data in your measurement. Please advise/clarify.
1. a) When no pump is running with 2 kW loading, the average voltage is 615 V, 6.67 A, pf 0.27...,
b) When one pump is running with 27 kW loading, the average voltage is 617 V, 35 A, pf 0.72...
2...
Thanks Mr stevenal
Let us get it right. Following are examples on some common items:
1. KVAHrs should be kVAh. Attention: NOT KVAh,
2. KVARHrs should be kvarh. Attention: NOT kVArh,
3. KV should be kV . Attention: NOT kv,
4. CB 'trip time' 0.1 s, Attention: NOT 0.1 S,
5. BB 'contact resistance'...
I have the following opinion.
1. In general, motor PF (kW/kVA) is ALWAYS low say (< 0.5) at low (< 0.4) loading. PF improves from say (> 0.70) say (> 0.8) loading. After that PF improves not very much from 0.8 to 1.00 loading.
2. Most LV supply from utility say < 500 A, do NOT penalize consumers...
I have the following opinion for your consideration.
1. No pump is running P = 2 kW, P =0.27
Note: a) with 2 kW shows that there are some other loads, (e.g. lightings) with low PF. Power transformers lightly loaded or some (smaller?) motors which are lightly loaded etc.
b) Many lighting...
'Wire your emergency stop in the circuit between the capacitor or other time delay circuit and the UV coil'.
I have different opinion.
Attention: this may defer between different OEMs, but the basic principle is usually the same.
1. The emergency stop , (if any) SHALL be wired directly to the...
@ Mr NickParker (Electrical)(OP)7 Oct 24 09:38
'.. whether there will be any issues with the stop push button (local or remote)... if I have implemented a time delay in the circuit during the transition period, when the operator presses the stop push button (either local or remote), do they need...
@ Mr NickParker (Electrical)(OP)
I have the following opinion for your consideration.
Check the ACB catalog, as it may defers between OEMs.
1. The time-delay device (from the same OEM) as the UV release may be adjustable say 0.5-.. s etc. It delays only the UV from dropping out. It does NOT...
@ Mr GHawk3798 (Electrical)(OP)6 Oct 24 01:26
'..I purchased a machine from China and they must have wired up the motor wrong because the pulley wheel is running counterclockwise when I need to it to run clockwise to properly work the machine..'
1. Please show the connection on the name-plate...
'..I wanted to inquire if there are any known requirements for gas detection meters for VRLA (valve-regulated lead-acid) batteries which are used in to serve data centres?..'
I have the following opinion for your consideration.
1. In US where NEC prevails, see Art 480-8 (a), Ventilation . "...
'...There was one charging motor. When a breaker was to be closed, the motor would be installed (It was quick and easy, just two wing-nuts held it in place). The breaker would be charged if needed and then closed. The closing spring would be re-charged ready for another close if needed. The...
'...The specification states that a minimum temperature rise of 10K is required for the cooling fluid, but the vendor's datasheet shows a coolant temperature rise of 15K. Based on this, the 15K provided by the vendor should be better than the 10K specified, Is my understanding correct?
I have...
I wish to stress/clarify the following.
1. '..A basic ACB DOES NOT DROP OUT ON THE LOSS OF SUPPLY VOLTAGE. Agreed.
2. For an ACB with an under-voltage release fitted:
a) With ACB in open state, when the voltage across the UV say > 85% rated voltage; the UV coil picks up. But, Note: The ACB...
@ Mr Hoxton123 (Electrical)2 Oct 24 16:35
' RMU = Ring Main Unit'
Thank you for your learned advice.
Can you kindly enlighten the relevance of RMU and what are the other items; 11KV EARTH cable and 65v leakage current.
Che Kuan Yau (Singapore)
'..The purpose of under-voltage release is a safety requirement to prvent a motor from starting automatically and unexpectedly when power is restored after an outage. It will be connected to the input or supply side of the ACB'.
I have different opinion.
1. In the usual case, a) when the voltage...
@ Mr David Adeola (Electrical)(OP)1 Oct 24 21:35
' OUTGOING 11 KV EARTH cable has 65v leakage current what could have been the causes if all the R.M.U were checked and confirmed to be okay'.
1. Sorry, I have difficulty to understand your question. Perhaps you would like to explain a) what is "...
