Talk:Rotary converter

message: Wasn't that unusual?  Were's most converters doing frequency conversions, thus using slip rings at both input and output?  ~~
: This article is wrong and needs to be cleaned up. Many people confuse the rotary converter with the Motor generator or rotary phase converter. All three of those devices are separate and should be treated as such. The rotary converter was an DC to AC or AC to DC converter. It could be started from the DC or AC side but DC starting was preferred as it allowed a smooth and gradual start using a resistive motor starter. I have never heard of a frequency converter that has a common shared set of rotor windings. The only other device that might have shared rotor windings would be the dynamotor (not dynamo) which was a DC only motor-generator which served as a DC transformer, boosting or bucking the DC voltage. I have to check my books but I dynamotors might have had seperate rotor windings and was a motor generator set. A frequency converter for AC would have been a motor generator setup which could share a common shaft and housing but have a completely separate set of windings for the motor and generator side ie each side is electrically isolated. Thaddeusw (talk) 14:41, 5 July 2009 (UTC)
thread_title: Two commutators

message: Rotary converter refers to a class of electrical machinery that was used to convert one form of electrical power into another form.
Wouldn't 'that is' or deleting 'that was' altogether be better?  Surely it cannot be guaranteed that none are in use anywhere in the world anymore.  —Preceding unsigned comment added by 85.211.159.106 (talk) 14:34, 20 January 2008 (UTC)
replies: text: It is definitely in the past tense, because before transistors or vacuum tubes existed, the rotary converter was the only option available for voltage/phase conversion. They were everywhere in the power grid and were a fundamental component of many power systems. Now they are gone, replaced by quiet nonmoving solid state hardware that needs no maintenance and spends all day just humming to itself. DMahalko (talk) 04:51, 19 May 2008 (UTC)
replies: text: Nope, they are still used to this day.  Every aircraft stand in many airports throughout the world use them to convert the local mains frequency to the 400 Hz required by the aircraft.  Although there are more modern solid state converters they are not particularly favoured. 20.133.0.13 (talk) 15:01, 10 February 2009 (UTC)
replies: text:  Hi, The system you are describing is called a motor generator set or MG set. The rotary converter was a rotating piece of machinery that converted AC power to DC and vice-versa. It was neither motor nor generator but a sort of bi-directional rotating rectifier/inverter. Its armature windings were shared for both AC and DC power, its stator windings were wired like a DC motor (compound/field/series/shunt wound). The rotor had a set of three or six slip rings for AC power on one side and a commutator for DC on the other. A motor generator set always has two separate and distinct rotor windings for the motor and generator head. The device might share a single shaft and housing or be two separate devices connected together by belt or shaft coupling. An MG set is not exclusively for AC<->DC conversion which is the case for the rotary converter. An MG set and rotary converter are two totally separate devices. Thaddeusw (talk) 14:27, 5 July 2009 (UTC)
replies: text: You are wrong.  Rotary converters can also (and are) used to convert one frequency to another (although the frequencies do have to be harmonically related).  The aircraft application given is by far the most common use these days, but historically, they were also used to derive the 16 2/3 Hz supplies for some railway systems.  For aircraft use at least, the converter itself is a single machine with seven sliprings.  Three slip rings are for the input 50 Hz three phase supply, and the remaining four are for the three phase and neutral 400 Hz output.  The machine has no shaft extensions.  Solid state converters are not favoured in the aircraft business because the output is not as purely sinusoidal as is desired - or at least that is the official position.  I have not encountered an aircraft rotary converter with anything remotely approaching a clean 400 Hz sinewave output.  86.157.171.34 (talk) 13:35, 21 January 2013 (UTC)
replies: text: I am not at all wrong. This article refers to the "Synchronous Rotary converter". You are thinking of a motor generator set, a completely different machine. Please read the Motor-generator article. If you are familiar with obsolete electrical machinery, the term "rotary converter" was used to refer to the "synchronous rotary converter". Today, the usage of the term has changed and can now refer to a variety of electrical machinery which converts one source of electric power to another. Many people simply do not understand this older terminology which causes confusion. Today, people hear the term rotary converter and think of a rotary phase converter (used to create 3 phase from single phase) or motor generator sets. And as far as solid state systems go, modern DSP driven IGBT switched PWM converters can get very close to pure sine, if not achieve pure sine. MG sets are preferred because they are rugged, simple and have no sensitive electronics. Though in some cases, solid state systems are used as they can be cheaper, light weight, easily portable and work off wide range of input voltages/frequencies without having to adjust anything. Thaddeusw (talk) 20:17, 23 January 2013 (UTC)
replies: text:  Synchronous rotary generators can change AC frequency too, although as noted, the frequencies have to have a simple harmonic relation. AFAIK, all of the railway 16 2/3Hz systems used them. I've not seen aircraft kit that wasn't an MG, but then these were just doing AC/DC conversion, as aircraft are almost exclusively either 400Hz or DC. There's just no need for AC frequency changing on aircraft. Andy Dingley (talk) 20:31, 23 January 2013 (UTC)
replies: text: Methinks you missed the point.  While you are correct that there is no need to change frequency within the aircraft power system itself, nevertheless the aircraft needs to be supplied 400 Hz power while it is parked on the ground when the engines and APU are not running.  This power is often supplied from the local 50 or 60 Hz mains power via a converter.  Whilst such a machine could, of course, be a motor generator set, most machines in the 50 Hz world are not.  They are a single rotary converter with no external shafts that convert 50 Hz to 400 Hz (a ratio of 8:1 which is easily achieved).  In the 60 Hz world the ratio is not simple enough (20:3) that a rotary converter can be used, and a motor-generator set is required.  86.157.171.34 (talk) 16:23, 25 January 2013 (UTC)
thread_title: Can this be proven?

message: As with many wikipedia topics involving old technology no longer in common use that nobody knows much about, this article has not been very useful for explaining the technology. I am working to add high-quality public domain illustrations and to improve the overall technical quality of this article. DMahalko (talk) 04:48, 19 May 2008 (UTC)
replies: text: Unfortunately this and the frequency converter article contain a circular reference with neither article explaining how a rotary frequency converter works. 20.133.0.13 (talk) 15:02, 10 February 2009 (UTC)
thread_title:  Improving this article 

message: While a motor generator and a rotary convert both convert electrical power from 1 voltage/frequency to another, they do it in 2 entirely different manners.
A motor generator converts the input electrical power, to mechanical power at the shaft, and then back to an electrical output.
A rotary convertor functions as a transformer, with mechanical rectification by means of the commutator, the synchronous rotation of the machine serving only to maintain proper phasing of this rectification. WuhWuzDat 05:01, 27 June 2009 (UTC)
thread_title:  Oppose merge with motor generator 

message: When used for AC to DC, how does the output voltage vary with load ? Does output voltage retain original no-load relation to the input AC voltage ? Were there mechanisms to manually or automatically adjust the output voltage ? - Rod57 (talk) 15:48, 5 November 2015 (UTC)
thread_title:  What voltage regulation ?