Orion AR612; class X/Y capacitors. - UK Vintage Radio Repair and Restoration Discussion Forum

TimS · 24th Nov 2006, 9:08 pm

This Orion, part-way restored, is an AC set so I would normally add an earth to the chassis. However the chassis is connected via two caps to the live and neutral AC input - I presume this is to minimise interference and put the chassis 'in between' the AC input voltages.

Would I be best taking out the caps and earthing the chassis or leaving things as they are (probably replacing the caps with new ones - class X presumably)?

-- Tim.

Ed_Dinning · 24th Nov 2006, 9:20 pm

Hi Tim, these caps should be class Y and the chassis can be connected to earth ONLY IF THEY ARE CLASS Y CAPS.
Class X caps are only for connecting across the mains. If they fails they normally self heal, but can let a lot of energy through in the process.
Class Y caps cannot fail except open circuit so present no danger when connected to earthed metalwork.

Ed

TimS · 26th Nov 2006, 6:56 pm

Can I just get rid of these caps altogether and earth the chassis so it would be like the other AC sets I have?

Tim.

ppppenguin · 26th Nov 2006, 7:07 pm

I'm not familiar with this set but if HT and LT are both via a double wound transformer then you can earth the chassis. This is allowed whether or not you have the Class Y caps from mains to chassis.

Beware of designs that do more subtle things like using an autotransformer or a tranny for LT and recitifed mains for HT.

TimS · 27th Nov 2006, 4:08 pm

Does 'double wound' just mean that HT and LT have separate windings?

Tim.

Chris_C · 27th Nov 2006, 4:21 pm

No! It means that the mains input winding is separate and insulated from the HT and LT secondary windings.
The only electrical path is through the transformer effect.

From the circuit diag. The Orion AR 612 does have a double wound mains transformer.

24th Nov 2006, 9:08 pm	#1
TimS Pentode Join Date: Jun 2005 Location: Forres, Moray, UK. Posts: 194	Orion AR612; class X/Y capacitors. This Orion, part-way restored, is an AC set so I would normally add an earth to the chassis. However the chassis is connected via two caps to the live and neutral AC input - I presume this is to minimise interference and put the chassis 'in between' the AC input voltages. Would I be best taking out the caps and earthing the chassis or leaving things as they are (probably replacing the caps with new ones - class X presumably)? -- Tim.

24th Nov 2006, 9:20 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Orion AR 612 Hi Tim, these caps should be class Y and the chassis can be connected to earth ONLY IF THEY ARE CLASS Y CAPS. Class X caps are only for connecting across the mains. If they fails they normally self heal, but can let a lot of energy through in the process. Class Y caps cannot fail except open circuit so present no danger when connected to earthed metalwork. Ed

26th Nov 2006, 6:56 pm	#3
TimS Pentode Join Date: Jun 2005 Location: Forres, Moray, UK. Posts: 194	Re: Orion AR 612 Can I just get rid of these caps altogether and earth the chassis so it would be like the other AC sets I have? Tim.

26th Nov 2006, 7:07 pm	#4
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Orion AR 612 I'm not familiar with this set but if HT and LT are both via a double wound transformer then you can earth the chassis. This is allowed whether or not you have the Class Y caps from mains to chassis. Beware of designs that do more subtle things like using an autotransformer or a tranny for LT and recitifed mains for HT.

27th Nov 2006, 4:08 pm	#5
TimS Pentode Join Date: Jun 2005 Location: Forres, Moray, UK. Posts: 194	Re: Orion AR 612 Does 'double wound' just mean that HT and LT have separate windings? Tim.

27th Nov 2006, 4:21 pm	#6
Chris_C Hexode Join Date: Jan 2003 Location: Darlington (DL3) North East U.K. Posts: 394	Re: Orion AR 612 No! It means that the mains input winding is separate and insulated from the HT and LT secondary windings. The only electrical path is through the transformer effect. From the circuit diag. The Orion AR 612 does have a double wound mains transformer. __________________ Chris C G8TJR Last edited by Chris_C; 27th Nov 2006 at 4:23 pm. Reason: added info