Adcock Shipley Bridgeport motor

[colin hamiltonParticipant @colinhamilton16803]

I'm just getting to know my bridgeport mill. The main motor is a bit unusual in has much it only gas 3 wires in the connector box. I have done a bit of research and it looks like this was standard for these English bridgeports. My motor plate is very faded but looks like it's badged as both 230/240v and 380/420V. Does this make it a 2 speed motor? Will it run on a single phase to 230V 3 phase inverter?

[colin hamiltonParticipant @colinhamilton16803]

[Chris Evans 6Participant @chrisevans6]

From what I can see in your unloading picture it is a "Varidrive" machine. I have one of these running from a VFD at 230/240 Volts.

[Brian MorehenParticipant @brianmorehen85290]

Is this a single phase machine with 3 leads Live Neutral & Earth , Or is this a three phase machine with 3 Live and a earth lead 4 Cables if a neutral is there for a light then ypu may have 5 Leads .

Regard Bee.M

[Anonymous]

Posted by colin hamilton on 16/01/2022 18:52:44:

Does this make it a 2 speed motor?

Dual voltage, not 2 speed. It needs 415V in star and 230V in delta. Should be a box on the motor with internal links to change between star and delta.

Andrew

[colin hamiltonParticipant @colinhamilton16803]

Im familiar with star and delta but this is different. It only has three wires and an earth in the connection box. It's a 3 phase motor

[colin hamiltonParticipant @colinhamilton16803]

D

[colin hamiltonParticipant @colinhamilton16803]

Posted by Chris Evans 6 on 16/01/2022 19:03:08:

From what I can see in your unloading picture it is a "Varidrive" machine. I have one of these running from a VFD at 230/240 Volts.

I'm new to all this so I may be misinterpreting you but I have a j head model and need to change speeds via a belt change

[AJAXParticipant @ajax]

I've taken apart quite a lot of single and three phase motors, but I don't claim to be an expert. As the data plate states this can be wired for 220v or 380v operation then it should be possible to change some links somewhere. I suspect if you open the motor up you'll find links behind the wiring box. If so, you should be able to wire for delta operation.

As an aside, here are two good books you may find useful.

Electric motors (16) and electric motors in the home workshop (24) in the workshop practice series.

[Brian MorehenParticipant @brianmorehen85290]

If your motor runs o/K at the moment it seems that this is a single phase motor . Your incomeing cable is a metal covered flexible cable and the outer is used for a earth connection but the green wire has also been used for this so it appears that this is wired for single phase use .How many wires are in this incomeing cable?

Regards Bee M

[Clive FosterParticipant @clivefoster55965]

That is a remarkably crude data-plate.

Normally motors capable of being configured in both Star and Delta have 6 terminals in the junction box witha set of links to get the coils in the appropriate order.

In the UK permanently wired motors on things like machine tools, especilly older ones, are commonly wired Star for 420 volts so changing needs digging into the internal wiring. Usually the data plate simply states 420 volts but I have encountered a couple that had details for 230 volt Delta connections on the data the plate as well with a simple punch or similar mark to identify which way the internal connections were set.

The first time I encountered such a motor I was unamused to find hard soldered connections after opening it up instead of the expected set of screw terminals to facilitate re-configration hidden under the junction box. It took a fairly forensic examination of the, somewhat aged, data plate to discover the indicating puch mark.

If you are lucky the reconfiguration connections will be on the back side of the visible board. Not something I've seen but I'm told it has been done.

Clive

[GordonHParticipant @gordonh]

Colin,

Your motor rating plate looks as if it has been sanded down, has a previous owner repainted your Bridgeport? I have a single phase, non-Varispeed Adcock and Shipley Bridgeport. The motor rating plate is painted, with bare metal only in places where details have been stamped. In addition, the label on the electrical cabinet also identifies the Voltage, phase and maximum current..

The picture of the connections which you show is the connection to the top of the motor. If the motor is 3 phase and configurable, the connections are likely to be in the box on the front of the motor, where the cable from the electrical cabinet terminates. On my machine, this only houses the Forward, Off, Reverse switch, is this the case on your machine?

Gordon

[colin hamiltonParticipant @colinhamilton16803]

I'm pretty sure it's 3 phase. When I went to view the vendor had it plugged into a three phase supply. In the main junction box (on the mill) there are a number of breakers and a transformer, which I think is for the feed motor.

Gordon- yes my picture is ofvghevmotor connections. The additional box just contains the rotary swith for starting and reversing.

I've had a look online and I think I've got the same set up as this chap.

[Chris Evans 6Participant @chrisevans6]

Posted by colin hamilton on 16/01/2022 20:17:20:

Posted by Chris Evans 6 on 16/01/2022 19:03:08:

From what I can see in your unloading picture it is a "Varidrive" machine. I have one of these running from a VFD at 230/240 Volts.

I'm new to all this so I may be misinterpreting you but I have a j head model and need to change speeds via a belt change

Sorry Colin, a quick look at the picture does indeed show a J head.

When my Varidrive machine was configured to run on a VFD the person that did it for me removed the knob for reversing and now that is done on the VFD.

[Clive SteerParticipant @clivesteer55943]

Colin

Although more modern motors have 6 terminals and usually brass jumper link some early motors had just 4 terminals. Each of the wires from the windings, there should be 6 in total, will be identified either by colour or some other form of marking. Note down what the connections are at the moment for use later.

For 380/420V (Hi Volts star connection) three wire from the winding would be connected to one terminal to form the star point and each of the other ends of the 3 windings would be connect to a single terminal to which the three phase supply is connected. This is most likely the connection arrangement you have at the moment.

For 220/240V (Lo Volts Delta connection) operation the three windings are connected effectively in a ring. So the end of one winding is connected to the start of the next winding.

However how does one know what are the start and finish of each winding if the motor doesn't have a circuit diagram on the terminal box cover. The three wires connected to the common star point , if connected for Hi Volts, are likely to be the finish of each winding.

So begin by isolating each wire from the star point and then use an ohm meter to find the match start of each winding and note the colour.

Clive Steer

[colin hamiltonParticipant @colinhamilton16803]

Posted by Clive Steer on 17/01/2022 10:32:18:

Colin

Although more modern motors have 6 terminals and usually brass jumper link some early motors had just 4 terminals. Each of the wires from the windings, there should be 6 in total, will be identified either by colour or some other form of marking. Note down what the connections are at the moment for use later.

For 380/420V (Hi Volts star connection) three wire from the winding would be connected to one terminal to form the star point and each of the other ends of the 3 windings would be connect to a single terminal to which the three phase supply is connected. This is most likely the connection arrangement you have at the moment.

For 220/240V (Lo Volts Delta connection) operation the three windings are connected effectively in a ring. So the end of one winding is connected to the start of the next winding.

However how does one know what are the start and finish of each winding if the motor doesn't have a circuit diagram on the terminal box cover. The three wires connected to the common star point , if connected for Hi Volts, are likely to be the finish of each winding.

So begin by isolating each wire from the star point and then use an ohm meter to find the match start of each winding and note the colour.

Clive Steer

Clive, thanks for this. If itvus currently set up in star configuration and I connect it to a 220v 3 phase supply would it still run (perhaps with reduced torque?)

[Clive SteerParticipant @clivesteer55943]

Colin

If the motor is wired for star and cannot be altered easily it will run on Lo Volts 3 phase but develop a quarter of the torque but probably sufficient for testing. The speed will be right whatever voltage the motor is feed with except for a more slip at the reduced torque.

Clive

[Anonymous]

Posted by Clive Steer on 17/01/2022 16:11:09:

……..develop a quarter of the torque…..

I'm puzzled, why a quarter? I would have naively thought it would be about 60%?

Andrew

[Clive FosterParticipant @clivefoster55965]

Andrew

Inverter Drive Supermarket have a nice blog post covering running a 400 V (nominal) star connected motor from a 230 V (nominal) inverter.

**LINK**

https://inverterdrive.com/HowTo/240V-Supply-to-a-400V-AC-Motor/

Basically you get full torque up to 29 Hz where the motor runs at 2/3 rds the nameplate speed so you do indeed get 60 % of the power. Theoretically 2/3 rds, 66 % but I imagine there are various detail devils deciding exactly how much.

Moi?

I'd work on 50 % of nameplate power and expect a healthy safety margin to exploit.

Hmm. Wonder how much air a Hydrovane makes at 2/3rds speed?

Clive

Edited By Clive Foster on 17/01/2022 17:59:00

Edited By Clive Foster on 17/01/2022 18:11:19

[Clive FosterParticipant @clivefoster55965]

Does anyone know, or have any resources allowing reasonable calculation, how much power is "enough" for a Home Workshop type Bridgeport user?

Less than any industrial user by some margin I'd think. Having to pay for both machine and cutters from whatever fraction of what's left over after covering the essentials defined by the distaff side is a strong disincentive to running sufficiently hard to shorten cutter life or damage the machine. Percy Piecework tends not to worry about short cutter life as the firm is paying!

My Bridgeport has a 1 1/2 hp 2J2 (Varispeed) head and I know I've never come close to running out of spindle power despite having it shuddering a time or to with ambitious cutter sizes and feeds.

Generally I run speeds and feeds about 2/3 rd that given in my old "Osbourne" free gift slide & box cardboard calculator. Which seems to work well enough that I'm not overly inclined to go hunting for "better".

Given the known inefficiencies of the Reeves drive on the Varispeed machine I'd be unsurprised to discover that there is little more than 1 hp at the cutter. The drive cover gets pretty warm indicating significant power is getting lost somewhere up there.

As Colin has the more mechanically efficient Vee belt drive head I think it quite likely that the 2/3 rds hp he will get from simply connecting his 1 hp star connected motor to a 230 volt Vfd may well be sufficent for anything he is likely to want to do. I woud be unworried about speed limitations. Mine goes ofver 1,500 rpm about every second muckspreading after the third blue moon of the year. Around August 2018 last time. Probably.

Clive

Edited By Clive Foster on 17/01/2022 18:38:59

[colin hamiltonParticipant @colinhamilton16803]

So I connected it up to the VFD I have for my lathe and it ran without any issues. I didn't have time to do any cutting so not sure about potential loss of torque yet.

It looks like the motor will dismantle without much effort so I might go looking for those pesky delta windings at the weekend!!

[Anonymous]

Clive: Thanks for the link. I took the original post to imply that if you had a motor designed to run at 415V, 50Hz and star connected, but ran it at 240V and 50Hz, the torque would drop to a quarter of the original value. I don't understand why that should be?

Andrew

[DiogenesIIParticipant @diogenesii]

G&M Tools   Apologies, Project Machinery have a used Transwave 1.2 Kw phase convertor listed, 415 output, £ couple of hundred.. ..an use?

Edited By DiogenesII on 18/01/2022 10:01:26

[colin hamiltonParticipant @colinhamilton16803]

Posted by Clive Foster on 17/01/2022 17:34:29:

Andrew

Inverter Drive Supermarket have a nice blog post covering running a 400 V (nominal) star connected motor from a 230 V (nominal) inverter.

**LINK**

https://inverterdrive.com/HowTo/240V-Supply-to-a-400V-AC-Motor/

Clive

Thanks for the very useful link. It is a very informative read. There are a number of very useful articles on their page. I phoned them yesterday to discuss VFDs in general and the lady who wrote that article spent at least half an hour taking me through it all. It was such a pleasure to speak to someone so informed and helpful I will always be going going to them for all my VFDs *I ordered 2 yesterday!!)

[Clive FosterParticipant @clivefoster55965]

Andrew

I suspect the confusion about torque and power loss was due to thinking in DC motor terms where half the voltage means half the current which means half the torque then if running at half speed you have 1/4 power. Or something of that lik.

Clive

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