Triad N68x Isolation Transformer

N-68X TRIAD, ISOLATION TRANSFORMER. N-68X TRAID, ISOLATION TRANSFORMER 230V 30/60 CPS, SEC. 115V 50 VAQUANTITY: 1CONDITION: NEW SURPLUSFollowing the purchase of any surplus item, product. N-68X Triad Magnetics Power Transformers POWER XFMR [email protected] 115/230V CHASSIS MOUNT w/LEADS/N-68X Q datasheet, inventory, & pricing. N-68X Triad Magnetics Power Transformers POWER XFMR [email protected] 115/230V CHASSIS MOUNT w/LEADS/N-68X Q datasheet, inventory, & pricing. Electrical and Power Distribution Transformers Power Transformers #N68X TRIAD MAGNETICS #N68X Transformer, Isolation; 115/230VAC Primary; Wire Leads; 50 VA.

Details

QUANTITY: 1

Switch

CONDITION: NEW SURPLUS

Following the purchase of any surplus item, product will be properly and professionally cleaned, painted, and tested. This is to ensure our customers of the quality, appearance, and function prior to shipment. Our extensive inventory also includes new items as well as hard to find obsolete items. We are a proud member of PEARL, and recondition all of our items to meet or exceed their reconditioning standards by our highly trained and experienced technicians. If it’s from The Motor Control Center you can be sure that you will receive the absolute highest quality at the absolute lowest price.

Triad n68x isolation transformer definition
Page 1 of 2
[ 37 posts ] Go to page1, 2Next
Previous topic Next topic
AuthorMessage
Posted: Jun Wed 12, 2013 2:43 am
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 744
Location: RI
Hi All,
Since I have acquired a couple 'hot chassis' radios, I suppose an isolation transformer would be a wise addition to go with my collection.
Any recommendations or advice what to look out for for a plu-in one?
ALSO, I found this in another thread, looks like this one could simply be retrofit into any hot chassis radio. Any thoughts on that and I did see that installing an isolation transformer is not foolproof, it greatly reduces the circiumstances under which touching the chassis could cause a shock. Is that true and anything else to the topic?
http://www.newark.com/triad-magnetics/n68x/isolation-transformer/dp/18M9252
Finally, what about isolating the radio internally to make it a not-hot chassis, I saw that this may involve quite a few re-connections, but how doable is it on a simple 5-tube radio?
Thanks...


Top
Triad N68x Isolation Transformer
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 29054
Location: Annapolis, MD
I have one of these:
http://www.ebay.com/itm/RCA-TV-ISOTAP-W ... 3a80e62338
I don't remember if I bought it on E-Bay or here, but they are very common on E-Bay (do an advanced search and select 'completed listings' to see actual sale prices.
Finally, what about isolating the radio internally to make it a not-hot chassis, I saw that this may involve quite a few re-connections, but how doable is it on a simple 5-tube radio?
The problem with this is that you want the chassis (for RF) to be at 'ground' potential---for shielding. AC/DC sets that have an isolated 'B-' will typically have a capacitor to the chassis and there is still some safety hazard.
I would simply use AC/DC sets the way they were intended----in an insulated cabinet with a back.

_________________
-Mark
'Voltage is fun to watch, but it's the CURRENT that does the work.'


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jun Fri 19, 2009 6:34 pm
Posts: 10163
Location: Long Island NY
The most important piece of advice in this regard is to watch out for so-called 'isolation transformers' that are really meant for EMI filtering in data centers and places like that. They are wired so one side of their output is grounded, which makes them unsuitable for the purpose intended here. To be sure, it is usually possible to modify them so they can be used for radio repair, but unless you are getting the transformer free, or nearly so, it isn't worth buying one of these things to modify, when you could just get one that is correctly made to begin with.
Another piece of advice is to pay attention to the power rating. Small isolation transformers (50 watts or 50 VA) have enough capacity for five-tube AC/DC radios, but nothing larger, and they will get uncomfortably hot after a while. A 200-watt, or 200-VA transformer would be a better investment in the long run, as it will handle nearly any household radio ever made with ease.
As for modifying old hot chassis radios to be safer, it's not as easy as it sounds. Many small AC/DC radios do not have room inside for transformers, and if you are going to rewire an entire radio to remove all connections to the chassis, you might as well stick a nice little solid state radio circuit board and a battery in there and be done with it! Major, irreversable modifications to an 'antique' never pay off. You'll end up with a radio nobody else wants, or if you do someday sell it, it will be for pennies on the time, effort, and parts you invested in it.
Instead, consider that our grandparents and great-grandparents certainly knew about getting shocked too, and took steps to prevent that from happening. It is better to make sure these protections are still effective, and fix them if not, than it is to try to modify an old radio into something it's not. Knobs on AC/DC radios should be wood, bakelite, or some other insulating material, without setscrews. The chassis should be in a plastic or wooden case, and if it originally had a back on it, you should replace it. Bottom chassis screws should be recessed if the chassis is 'hot,' and I either make plastic covers for them where practical, or change the metal hardware for plastic if not. If the case is metal, there were probably rubber bushings which may have disintegrated by now to isolate the chassis from the case. New bushings would have to be installed.

_________________
'Hell, there are no rules here--we're trying to accomplish something!'
Thomas A. Edison


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Aug Mon 17, 2009 4:11 pm
Posts: 3585
Location: DFW Texas
Hi All,
ALSO, I found this in another thread, looks like this one could simply be retrofit into any hot chassis radio. Any thoughts on that and I did see that installing an isolation transformer is not foolproof, it greatly reduces the circiumstances under which touching the chassis could cause a shock. Is that true and anything else to the topic?
http://www.newark.com/triad-magnetics/n68x/isolation-transformer/dp/18M9252

THat transformer works great for mounting inside AA5 radios. It doesn't provide very much power but is large enough for most if not all AA5 radios. I've used it on several radios that I want isolated permanently. I've also use it on two home brew radios I've built.
The way I understand it, and someone will correct me if I'm wrong, is that if you touch a radio chassis that is not isolated by a transformer and then you touch a ground you will get a shock. If your radio is isolated and you touch ground you will not get a shock. But if you complete the circuit by touching two points with a difference in voltage you will still get a shock even if using and isolation transformer. (Transformer in the paragraph above is understood to mean an Isolation Transformer.)

_________________
The lucky ones realize the 'Good Ole Days' while they are still in them!
AA5LP


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7448
Location: Toledo, Ohio
I use a BK TR-110. I like it because the isolated output voltage is adjustable from 90-140 VAC.

_________________
Jim
KE8GMW
------------------------
'AC volts and DC volts and little lamps and lities...'


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jun Fri 19, 2009 6:34 pm
Posts: 10163
Location: Long Island NY
The story on isolation transformers is this. Next time you are in a residential area with overhead power distribution, follow the wires. In most places, you'll see a single high voltage wire on insulators near the top of the poles. Every so often, that single wire is tapped into a 'pole pig' transformer. The 'pig' then has low voltage outputs which run on lower wires to the houses.
Ever wonder how that works, with only a single high tension wire feeding the primaries of the transformers? The other side of the primary circuit is ground, and the ground connection is made at the service entrance of each house. What's more, to protect the occupants and structure in case of a high voltage flash-over or insulation breakdown, one side of the secondary (the neutral) is also connected to ground at the service entrance. Any current crossing directly from primary to secondary encounters a short circuit and blows the pole fuse.
The consequence of this is that it now becomes possible to complete a circuit between the 'hot' side of the AC line in the house, and any grounded object. This is unfortunate if you happen to become an accidental conductor between something that is electrically 'hot,' say an old AC/DC radio chassis that has been plugged in so the chassis is on the high side of the line, and ground, perhaps in the form of a damp concrete basement floor.
In this situation, an isolation transformer provides a source of 120-volt AC power in which the neutral is not referenced to ground. So even if you touch one side of the output and ground, there is no circuit back to ground, and no shock results. Of course it is still 100% guaranteed that you will get a shock if you connect yourself across the transformer's output, or across the B+ of the radio, so it's not a panacea. Further, when using an isolation transformer on a service bench with a 'hot chassis' device, remember that the ground clips on your test equipment (which should be grounded) will re-reference the isolation transformer to ground. The isolation transformer will protect your test equipment in this case, and at least you won't have a big metal chassis that's live, but the chances of a ground fault shock occurring if you accidentally touch other connections in the set and ground at the same time have returned.

_________________
'Hell, there are no rules here--we're trying to accomplish something!'
Thomas A. Edison


Top
Post subject: Re: Recommended Isolation Transformer
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 9332
Location: Latham NY 12110
An old tech once said that is more about protecting your test equipment than yourself.


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jun Fri 19, 2009 6:34 pm
Posts: 10163
Location: Long Island NY
Or as one of my former bosses said, 'Techs are replaceable, but test equipment costs money!'

_________________
'Hell, there are no rules here--we're trying to accomplish something!'
Thomas A. Edison


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 29054
Location: Annapolis, MD
In most places, you'll see a single high voltage wire on insulators near the top of the poles. Every so often, that single wire is tapped into a 'pole pig' transformer. The 'pig' then has low voltage outputs which run on lower wires to the houses.
Hmmmm---I have NEVER seen this arrangement. I'm from California-----now I'll start observing Maryland power poles.
BUT---AFAIK, All residential power systems ground the neutral at the main panel, so----for the purposes of this thread---what happens upstream is irrelevant.

_________________
-Mark
'Voltage is fun to watch, but it's the CURRENT that does the work.'


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 31285
Location: Maryland 20709, USA
In most places, you'll see a single high voltage wire on insulators near the top of the poles. Every so often, that single wire is tapped into a 'pole pig' transformer. The 'pig' then has low voltage outputs which run on lower wires to the houses.
Hmmmm---I have NEVER seen this arrangement. I'm from California-----now I'll start observing Maryland power poles.
Quite common (dare I say 'standard'?) around here.
- Leigh

_________________
73 de W3NLB
http://www.AtwaterKent.info
Click 'Grebe Stuff' for Synchrophase info


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 744
Location: RI
I've actually seen that one-wire neighborhood power bus scheme too, and puzzled over it, until now!


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 744
Location: RI
I am actually finding several on ebay from 1.25Amp (150w) on up... anything to look out for or if it is an 'isolation transformer' is that all I need to know.
Also, I do not have a VARIAC, do those isolate and should I go that way to get two birds at once if so?
Also, final test when I get something, is the definitive test a continuity check between both legs and the chassis/ground at the radio and the input (power cord) of the iso transformer?
Thanks, and anyone else wishing to share what they use on their bench for safety isolation, please pipe up.


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Aug Mon 17, 2009 4:11 pm
Posts: 3585
Location: DFW Texas
A variac is NOT and isolation transformer and can wait.
Check the resistance between the primary leads and the secondary leads. It should be infinite.
Read also this thread. viewtopic.php?f=8&t=93030

_________________
The lucky ones realize the 'Good Ole Days' while they are still in them!
AA5LP


Top
Post subject: Re: Recommended Isolation Transformer
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 9332
Location: Latham NY 12110
if you can find one of these, Viz Isotap WP-27A, it takes up a lot less space and works great.
http://www.ebay.com/itm/VIZ-Isotap-II-W ... 338216280c


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 744
Location: RI
Hi Lou, thats the one I was looking at on there, but wanted to learn more first then somebody bought it. Figures!


Top
Post subject: Re: Recommended Isolation Transformer
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 9332
Location: Latham NY 12110
That unit was real nice almost looked new. I have had one for years and use it a lot. There is another one on now but it looks real ratty and the guy wants $76 for it.


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 744
Location: RI
Willl THIS one work?
http://www.ebay.com/itm/Dale-Fluke-IT400-Medical-Grade-Isolation-Transformer-110V-NEW-IN-ORIGINAL-BOX-/161010666194?pt=BI_Circuit_Breakers_Transformers&hash=item257cfbcad2


Top
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 31285
Location: Maryland 20709, USA
Willl THIS one work?]
It appears that it will, although I can find no datasheet on the product.
It's rated 350 VA, which is quite sufficient for vintage electronic work.
I would put a plastic safety plug in one of the outlets, to prevent accidentally plugging two pieces of equipment into the transformer inadvertently.
- Leigh

_________________
73 de W3NLB
http://www.AtwaterKent.info
Click 'Grebe Stuff' for Synchrophase info


Top
Triad N68x Isolation Transformer
Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 744
Location: RI
Hi Leigh,
I didnt think of that... plugging two equipt into the same iso transformer is a safety threat?
-Chris


Top

Triad N68x Isolation Transformer Power Supply

Triad n68x isolation transformer definition

Triad N68x Isolation Transformer Definition

Post subject: Re: Recommended Isolation Transformer
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 31285
Location: Maryland 20709, USA
I didnt think of that... plugging two equipt into the same iso transformer is a safety threat?
It might be... all depends on the specifics of the equipment involved.
Vintage iso's typically had a single outlet, to preclude that possibility.
Best to use the iso to power the radio being serviced, and power everything else from an outlet strip as usual.
- Leigh

_________________
73 de W3NLB
http://www.AtwaterKent.info
Click 'Grebe Stuff' for Synchrophase info


Top

Isolation Transformer Boat

Page 1 of 2
[ 37 posts ] Go to page1, 2Next