Single Pole Contactor - clarify different supplier costs

Thread Starter

tbb2

Joined Jun 27, 2014
14
I need to replace a single pole contactor on a Carrier heat pump.
Though I find single pole contactors with equivalent electrical specs, I also find a 300%+ variation in cost.
A contactor that actually has one of the two Carrier Brand numbers on it is the highest priced.
Is this a case of OEM versus aftermarket manufacturer or is there an aspect of the contactor required specs I am missing?
From experience on other machines I do not find OEM to be the gold standard.
Is a single pole contactor a single pole contactor?
Can I assume different suppliers contactors will have higher and lower number of switch count life spans?

Thank you
 

Thread Starter

tbb2

Joined Jun 27, 2014
14
You are right. I am missing the difference which the point of the question.
Well I suppose you are implying an answer Wolframore, that there are variations in single pole contactors.
What variations are there in single pole contactors other than the operating electrical specs?

Since product numbers are all different what details do you want?
The replacement is for a Carrier: Heat Pump 25HNA624 0030020; #3100-15Q228 ... HN51KC024.
What I am comparing it to is a White-Rodgers: #94-388.
 

Wolframore

Joined Jan 21, 2019
2,283
I’m sure the differences will be minor. As long as they’re rated for the correct solenoid voltage and the contacts are rated for correct voltage and current rating you should be fine. There may be some minor differences in the holding current and mounting.
 

Thread Starter

tbb2

Joined Jun 27, 2014
14
The 'should' is what I am trying to dispel.
What are you calling a 'Holding Current'?
Do you refer to the FLA?
 

Wolframore

Joined Jan 21, 2019
2,283
Without actually getting it and trying it or testing it, it will remain a should. Even if everything is correct spec wise, there could be manufacturing issue which means it’s never a 100% yes. 99% sure it will work for you. Is that better? If you don’t want to take a chance get the original
 

MisterBill2

Joined Jan 23, 2018
8,808
Holding current is the coil current in the contactor after it has operated and all the motion has been moved. The big consideration is the contact current rating, followed by the operating coil current and voltage rating, and the duty cycle rating. Beyond that the terminals for line and load connection matter for a replacement device. Some devices last longer than others, price is seldom the determining variable.
 

Thread Starter

tbb2

Joined Jun 27, 2014
14
My concern was with what makes one pole contactors different.
From the responses there are aspects of the switch that are not specific to the VAC, FLA, LRA, RES numbers and mounting.
So, what I am hearing is, the best match by production number is recommended.
I still am skeptical but do not have the wherewithall to do side by side studies of parts.
 

MisterBill2

Joined Jan 23, 2018
8,808
There have been two primary categories of contactors for a long time, which are "motor starting" and "Non-motor starting", and within that realm have been "tungsten" rated and "others".
Motor starting service usually has a longer period of high load, and Tungsten service has a very short period of high load current.
So the TS should get a contactor rated for motor starting, it seems.
 

shortbus

Joined Sep 30, 2009
8,595
My concern was with what makes one pole contactors different.
Did you see this video?
A single pole contactor is probably more expensive because they don't make as many of them. The few made and sold makes the price higher on many things.
 

Thread Starter

tbb2

Joined Jun 27, 2014
14
Gentlemen thank you - but I am just trying to understand what, if anything, differentiates one-pole contactors.
The price delta is there but only another cause for the questions.

I took two paths. One is to look at the VAC, FLA, LRA, RES numbers and the second is to look at the product numbers (?), both with overall configuration, on the original part. The first provides a huge selection the second a very small selection. There are price differences but they are not exclusive to my decision.

Is there something inherently different in the product numbers or are VAC, FLA, LRA, RES numbers all there is to it?
Are the price variations quality or inflated OEM markup?
 

MisterBill2

Joined Jan 23, 2018
8,808
It may be that if there is enough room for a 2 or 3 pole starter that one of them, with similar ratings, may be a better choice. If one pole becomes pitted and stops being reliable changing to the next pole could allow correct operation again for a while.
I recently discovered that my own home HVAC compressor has only a single pole contactor, although the compressor runs on 240 volts with neither side neutral, only one side is switched. Shile that works I consider it a shabby design, and when it becomes convenient I will change that to a 2-pole contactor device. Of course, having such on hand makes it much cheaper to do.
 

Thread Starter

tbb2

Joined Jun 27, 2014
14
After comm with a sales rep of a contactor manufacturer (HC) I may have a part of an answer. My comm was to sort the disparity in the HC product numbers between two seemingly identical contactors and the nomenclature in the HC catalogue.

First, the additional product number identifies mass production parts for specific buyers. So two different companies can have the same part with two different secondary HC numbers. So the part can be cross referenced to a specific buyers equipment.

Second, the variation in part of the HC nomenclature AA or AB turns out to be the type of terminal screw attachment. The AA was on the less expensive and the AB on the more expensive. The AB and AA terminal screws have different lengths and AB is often used for ring or fork connectors and the AA has a square washer that bites into a wire. The point is made that the terminal screw torque is critical to getting a solid connection so excess resistance does not burn out the contactor prematurely.

Does this help explain the contactor I need? Not wholly, the AB I have uses a forked connector seemingly by-passing the need to bite into a wire.

So back to where I started. Buy contactor with matching manufacturer part numbers, just to be safe ... until they become obsolete.
 
Top