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Functioning of Siemens 3TK28 05 Emergency Relay

11/28/2017 2:36 AM

I have gone through the manual of this emergency relay. But not able to under stand its function. This relay is used in our plant in Simadyne D controller and suspecting that this relay is malfunctining.

plz help

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Guru
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#1

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 2:56 AM

This world has almost as many telephones in it as it does people. So, what's wrong with picking up the phone and discussing the problem with the equipment manufacturer?

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#2

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 3:28 AM
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Guru
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#3

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 3:55 AM

<...not able to under stand its function...>

The people in #2⇑ also carry out training on the use and maintenance of their products.

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Guru
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#4

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 5:27 AM

Can't give you any useful guidance without either writing a lengthy essay about Safety Relay operation, or knowing your particular circuit requirement.

Emergency stop/guard? Single channel/2 channel? Auto/manual restart? Probably also need a link to your circuit diagram.

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#5
In reply to #4

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 9:29 AM

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Guru
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#6
In reply to #5

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 9:37 AM

Afraid that's not readable.

While you're sorting out somewhere to post it (Dropbox?) and sending us a link so it's legible, can you tell us why you suspect it's faulty?

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Guru
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Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting ["brexit" - ugh] as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
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#7
In reply to #6

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 10:03 AM

If the Original Poster is <...not able to under stand its function...>, the chances of an explanation that is easy to understand are quite low.

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Guru
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#8
In reply to #7

Re: functioning of Siemens 3TK28 05 emergency relay

11/28/2017 10:07 AM

Sadly true. I like to try to give a bloke a leg up, tho'.

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Guru

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#9

Re: Functioning of Siemens 3TK28 05 Emergency Relay

12/04/2017 5:25 PM

I have looked at the manual and can see that section 3.8.1 covering 3TK2805 relay matching your posted image of relay does not show "circuit of what is in the box". This is not helpful in understanding function.

I found the manual at https://cache.industry.siemens.com/dl/files/445/58843445/att_904331/v1/manual_safety_relay_3TK28_en-US.pdf

The following is my best guess. Image suggests control voltage to box is 24 VDC.

  1. This is basically a relay with 5 normally open contacts, to open dangerous circuits. The safety emphasis is that when the normal control circuit or emergency stop demands off, these 5 contacts are off.
  2. To this end two relays K2 and K3 are in the box with coils in parallel. One output N/O e.g. terminals 13 & 14 on the box is really an N/O contact of K2 in series with an N/O contact of K3. K2 & K3 are identified as Channel 1 and Channel 2 by the lamps on the box. In addition, in series with the pair of N/O contacts, is an N/C contact of K1. See figure 3-65 of manual.
  3. Obviously K2 and K2 must both work OK to close the 13-14 circuit - Channel 1 & 2 lamps must both be on.
  4. I guess K2 & K3 both have extra N/O and N/C contacts wired to the coil of K1 so it energises if K2 and K3 are NOT in the same state i.e. an N/O K2 in series with N/C K3 paralleled with N/C K2 in series with N/O K3. Normally, K2/K3 may momentarily differ due to time tolerances during energise, but K1 has a slow energise to avoid spurious operation. Hence if there is a discrepancy K2 to K3, K1 operates to ensure a double break of the output circuits.
  5. N/C contacts of K2, K3 in parallel to terminals 65,66 allow external control to remotely detect if only one of K2, K3 functions after start signal is given.

I think there is something wrong with timing diagram fig 3-64, which makes 25 ms look longer than 30 ms! I think it really means that the opening time of output contacts after de-energise of control input is less than 30ms, closing time is > 25ms [or maybe output should be off for 25ms before reclose else residual coil current may affect energise time] and an extra 30ms should be allowed before checking terminal 65-66 circuit.

I would think that usually a fault would be indicated by one channel lamp ON and the other OFF, but obviously the definitive test is with ohmmeter on output terminal pairs like 13,14 or 23,24 etc.

If you want more definite info, the manual gives, for further information, http://www.siemens.com/sirius/technical-assistance - who could give you the internal circuit diagram.

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Guru

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#10
In reply to #9

Re: Functioning of Siemens 3TK28 05 Emergency Relay

12/04/2017 5:30 PM

Apologies! item 3 should read "K2 & K3".

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#11
In reply to #9

Re: Functioning of Siemens 3TK28 05 Emergency Relay

12/06/2017 6:53 AM

Sir we have checked the relay in cold(without power and in hot (with power) condition doing the same shorting and looping as shown in the drawing. plz check the result and comments whether the relay is defective or not?.

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Guru

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#12
In reply to #11

Re: Functioning of Siemens 3TK28 05 Emergency Relay

12/06/2017 6:28 PM

Not clear what you are testing or what result is....

  1. Which diagram - the one you posted of your site connections, which cannot be seen clearly, or a diagram from relay manual?
  2. Is the current 0.2 Amp current to terminals A1, A2 or the test current for contact resistance?
  3. What are e.m.f. [AC/DC?] & load resistance of contact test circuit e.g. to 13-14?
  4. When you write "varying" what is actual range of variation of resistance and do you mean closed contact resistance varies with time after closure or different resistance at each test closure you make when repeated several times.
  5. With no power to relay, 65-66 should be closed, so "always open" looks like defect. Since there are N/C contacts of K2 AND K3 in parallel to 65-66, this looks more like broken connection than contact failure - unless both have been burnt open by major overcurrent in monitor circuit.
  6. All 5 output circuits appear to close - what are channel 1 & 2 LED lamps doing?
  7. You would need to show that outputs do not close if only circuit 1 or circuit 2 is energised & that K1 functions as expected to be sure the safety features of the box are working.
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#13
In reply to #12

Re: Functioning of Siemens 3TK28 05 Emergency Relay

12/07/2017 2:54 AM

plz find the reply in BOLD AND UNDERLINED

Not clear what you are testing or what result is....

  1. Which diagram - the one you posted of your site connections, which cannot be seen clearly, or a diagram from relay manual?- X4, X3, X1, X5 SHORTED. A2, X6 SHORTED
  2. Is the current 0.2 Amp current to terminals A1, A2 or the test current for contact resistance?---current to terminals A1, A2
  3. What are e.m.f. [AC/DC?] & load resistance of contact test circuit e.g. to 13-14?--NOT MEASURED
  4. When you write "varying" what is actual range of variation of resistance and do you mean closed contact resistance varies with time after closure or different resistance at each test closure you make when repeated several times.--- RESISTANCE IS VARYING AT EACH CLOSURE IN THE RANGE OF KOHM
  5. With no power to relay, 65-66 should be closed, so "always open" looks like defect. Since there are N/C contacts of K2 AND K3 in parallel to 65-66, this looks more like broken connection than contact failure - unless both have been burnt open by major overcurrent in monitor circuit.
  6. All 5 output circuits appear to close - what are channel 1 & 2 LED lamps doing? -- channel 1 & 2 LED lamps GLOW
  7. You would need to show that outputs do not close if only circuit 1 or circuit 2 is energised & that K1 functions as expected to be sure the safety features of the box are working.
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Guru

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#14
In reply to #13

Re: Functioning of Siemens 3TK28 05 Emergency Relay

12/07/2017 1:41 PM
  1. OK, that is everything On.
  2. Looks like K1 & K2 coils energised. About 0.1 amp each.
  3. High current contacts cannot be expected to be low resistance when tested with digital multimeter DMM, which puts < 1 volt and < 1 mA to test circuit. This is particularly true once contact has been used for high voltage breaksand is worn. About 6volts and 0.1 amp is realistic for single contact, noting you have 3 contacts in series, I would not use less.
  4. Per 3., you cannot expect repeatable result with low voltage. I forgot to write, about coil circuits, that the presence of LED (1.2 volt diode drop or more) in series means you will read little if anything with DMM. There might be other diodes in the box. Check with 9V battery and 1k resistor to be sure have a coil (maybe 250 ohm), then apply 0 to 24VDC [variable test bench supply] and measure current to coil. Most LED will conduct only microamp at 24V in reverse direction.
  5. OK, no surprise.
  6. I think you need to show that energising K1, with 1 & 2 LEDs glowing, cuts off all 5 output circuits and that only one channel ON (maybe X1 or X3 off) causes K1 coil to energise. However, I have not yet understood which terminals of X1 - X6 are coils or what interconnection is. It would help if you could test to find out.
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