new to chillers

[Tech Rob]

[johnnyb]

with respect to the windings. The applied source voltage is the same but in the y configuration there are two windings in series with each phase of the source which cuts the voltage per winding in half which should cut the power to 1/4. but I do not remember how the math works out in reality and I'm not going to look it up again. Thanks for all the replies , guys. And girls if any of you are girls. (Not meaning you guys are girls)

[milkyway]

,!!!!MEH!!!!,!,!

#1
Wye delta uses at least 3, and sometimes 4 contactors, depending on if it's open or closed transition. It's not a reduced voltage starter. It's a full voltage, reduced inrush type of starter.

#2
The wye-delta starter has no means of reducing the voltage at the motor terminals. However, the effect on the motor is the same as reduced voltage because in wye, the motor only sees 58% of the line voltage through each winding.*
Rob

#3
a wye delta motor is NOT a reduced voltage motor. it recieves the full voltage (that the building can provide) at all times (except in Open Transition starters).
jay guy*

#4

a wye delta motor is NOT a reduced voltage motor. it recieves the full voltage (that the building can provide) at all times (except in Open Transition starters).

Most (but not all) VF drives are reduced voltage starters.
Depending on how you look at it, a Solid State Starter is reduced voltage starter (but not really).
Primary Resistor is reduced voltage starter.
MultiPoint Reduced Voltage is a reduced voltage starter.
Auto Transformer is a reduced voltage starter.

a wye-delta starter is not a reduced voltage starter. changing the order of the windings does not change the incoming voltage. it does change the resistance and reactance of the motor...but the motor/starter is still full voltage.
Jay guy

#5
I got out some of my motor/starter books and it does say in both of them that it is similar to a reduced voltage starter but does not classify it as a reduced voltage starter, so my apologies. *

#6
The reason it is refered to as a reduced voltage starter is that the applied voltage passes through multiple windings, thus voltage is dropped at each winding. Hence, the term reduced voltage. Who would have ever imagined that a simple starter would arouse this much traffic.

#7
This is a good explanation of what approach is. But to expand a little, approach tells us how efficient our heat transfer is. A high approach means a poor heat exchange is taking place. Most likely culprit is waterside fouling. a low approach means there was a good heat transfer. An ideal approach is 0 which would mean the heat transfer efficiency is 100%, which is not really possible, but we can get really close

#8
the correct formula for inrush current on ac induction motors includes: magnetizing resistance, magnetizing reactance, motor winding resistance, motor winding reactance, rotor resistance and rotor reactance and of course voltage.

AND THIS IS HOW IT WORKS!
Thank god ness for this forum, canT find this in a 4 hour class,

[Healey Nut]

Lets just call it "reduced inrush " and be done with it . Can we put this one to bed now ??

[Tech Rob]

AND THIS IS HOW IT WORKS!
Thank god ness for this forum, canT find this in a 4 hour class,

In the 5 years I've been browsing and posting here, I've learned so much, and I know that I'm a better tech for it. I espouse the virtues of HVAC-Talk to everyone I work with.

[henpeck]

I'll second ya both, good stuff - good stuff





Sent from my iPhone using Tapatalk

[jayguy]

Lets just call it "reduced inrush " and be done with it . Can we put this one to bed now ??

reduced inrush works for me!


type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type, type...

...didn't want SW to feel left out.

[milkyway]

HAHA





doesnt look like bed time.,

[spinning wheel]

Thanks for the thought Jay.

[Mongo and me]

OK, I have read this post and now have all kinds of questions, why ----- I have no idea why, I just do .................

LOVE IT ALL..........

And to the closing I must add my most understood line from a great person some time ago,

"I remember when ELECTRICITY, was just electricity!"

[supertek65]

no it would be a mega super dooper hella reduced electromotive force starter!!!!!

electrical 101 says that there is voltage drop across ALL windings no matter how many there are in series...1 or 2 or 1000.

does this mean that all wye wound motors are reduced voltage motors? if i build a motor with 4 windings in series (instead of 2, but of the same total horsepower) will my motor be considered a 'Super Reduced Voltage' motor/starter? will this make my starter have a lower inrush than everyone elses?

(the answer is no)

[heavymetaldad]

i like pudding!

i like nickel never seize, thinned out with some 5gs.

[dumnut]

Depending on how you look at it, a Solid State Starter is reduced voltage starter (but not really).

I wonder why you say “but not really”?

If the electronic switch (gate) is triggered after the cycle peak then it would defiantly seem to be a reduced voltage starter. Even if the switch is triggered before the cycle peak, such that the peak voltage is included in the cycle, the nominal voltage as read by a volt-meter is still going to be reduced.

I’ve even been toying with the idea of using a solid state starter to send the very tail end of the power cycle to the motor windings of a small hermetic compressor, as a way to eliminate the crank case heater. The windings themselves would become the heater and with the voltage turned low enough the motor itself wouldn’t budge.

Other than that I agree with your assessment.

[jayguy]

I wonder why you say “but not really”? ...

like i said, it depends on how you look at it.

during the voltage wave cycle, as the motor is energized, it does recieve a lower than normal voltage signal during the first half of the ramp up...however, about half way in the start up cycle, it recieves the full voltage signal. the SSS just cuts off the voltage wave form at different points in the wave as the chiller comes up to speed. you could say that this was a form of reduced voltage, but i believe that it is a full voltage starter with a wave form modification versus actually reducing the voltage (and giving ith the full wave form) to the motor....this one is a little tricky.

my main point to all of my arguing was that the unit (motor, starter or motor and starter) recieves full voltage but the unit changes resistance/reactance to gain a lower amperage inrush. while some were saying that it was all semantics, there really are starters out there that reduce the voltage that the motor recieves (without changing the motors characteristics) to achieve the lower inrush.

[dumnut]

like i said, it depends on how you look at it.

during the voltage wave cycle, as the motor is energized, it does recieve a lower than normal voltage signal during the first half of the ramp up...however, about half way in the start up cycle, it recieves the full voltage signal. the SSS just cuts off the voltage wave form at different points in the wave as the chiller comes up to speed. you could say that this was a form of reduced voltage, but i believe that it is a full voltage starter with a wave form modification versus actually reducing the voltage (and giving ith the full wave form) to the motor....this one is a little tricky.

Ah, now I see where you are coming from.

my main point to all of my arguing was that the unit (motor, starter or motor and starter) recieves full voltage but the unit changes resistance/reactance to gain a lower amperage inrush. while some were saying that it was all semantics, there really are starters out there that reduce the voltage that the motor recieves (without changing the motors characteristics) to achieve the lower inrush.

And I support your efforts to correct that confusion. Some of those posts (at least one) could easily be misinterpreted to give the impression that the delta configuration is far more efficient that the wye configuration, which is simply not true. I think you also touched on that confusion. We owe you a debt of gratitude for your efforts.