Trouble finding replacement part for power relay

LesJones

Joined Jan 8, 2017
4,174
Thanks Max & Ron, So it probably is a 120 volt DC but I would like to complete the schematic to be sure before telling the TS to order the relay. (Or to go for the SSR solution)

Les.
 

Thread Starter

Jolteon

Joined Feb 6, 2018
24
Yes, as to things like Contact Form , this link gives a good overview. Problems can arise when the actual pin out on for example, a board mounted relay are not the same. This leaves the end user crawling through endless data sheets looking at dimensions and what the actual pin out is. My reference to form when I mentioned form, fit and function was to finding a relay which would fit in the space provided. That or start getting creative. :)

I was surprised the system manufacturer did not simply have one off the shelf.

The existing relay appears to have a 110/120 VDC coil. If I could not find a suitable mechanical replacement I would likely just shove an SSR in and be happy. 90 to 240 VAC output SSRs are pretty common. I would settle for the common 3 - 32 Volt DC control voltage and simply divide the now incoming coil voltage to a usable control voltage. Not like the control voltage requires any current and a simple 4:1 or 5:1 divider should work fine. That's likely how I would try to go about it.

Ron
I briefly looked into voltage divider. I'm a complete rookie but do I just add a pair of resistors to divide the voltages like the image shown below? If yes, where do I add them?
Voltage Divider.jpg
 

Thread Starter

Jolteon

Joined Feb 6, 2018
24
Thanks Max & Ron, So it probably is a 120 volt DC but I would like to complete the schematic to be sure before telling the TS to order the relay. (Or to go for the SSR solution)

Les.
I apologize for the bad image quality of the etch board. Hopefully the following is clearer as I shone a light behind it.
PCBEtchLight.JPG
 

LesJones

Joined Jan 8, 2017
4,174
Here is the schematic.

120218.jpg
This shows that my assumption that the relay coil is 120 volts is wrong. There is effectivly a 5K resistor in series with the relay coil. we will have to work out which relay coil version in series with with 5 K matches about 120 volts DC. I don't know what connects to the connector X1 but a think a switch will connect it's centre pin to the mosfet drain.

Les.
 

GopherT

Joined Nov 23, 2012
8,009
Do you know where they are located/shipped from?
I think they are in Texas. Most manufacturers do no ship direct to end customers unless you buy a bunch so ask who their distributors are near your city (or a US distributor that ships to Canada.
 

LesJones

Joined Jan 8, 2017
4,174
Have you checked that the pinout dimensions on the data sheet from the link that Ron provided in post#3 ? After looking at the coil resistances of the relays in the data sheet it looked like it could be the 110/120 volt one or the 48 volt one. (With 5K in series with either of them would require about 150 volts. ) It is reasonable to expect this voltage across C2 as it will be somewhere between the RMS and peak value of the input voltage. Working out the dissipation in the series 5K resistor with the 48 volt coil gave a value of about 2 watts. As the two 10 K resistors look to be about 1/2 watt rating it suggests that is more likely to be the 110/120 volt relay.
COULD YOU PLEASE AT LEAST TRY TO MEASURE THE COIL RESISTANCE ON YOU RELAY.

Les
 

Thread Starter

Jolteon

Joined Feb 6, 2018
24
Here is the schematic.

View attachment 145757
This shows that my assumption that the relay coil is 120 volts is wrong. There is effectivly a 5K resistor in series with the relay coil. we will have to work out which relay coil version in series with with 5 K matches about 120 volts DC. I don't know what connects to the connector X1 but a think a switch will connect it's centre pin to the mosfet drain.

Les.
Yes, X1 is connected to an auto/on/off switch. At the beginning, I thought this was just a general electronics forum but realized thereafter, it is geared towards electrical engineering which I have no experience with. When I googled "electronic circuit forum", this appeared as the top search and I registered, hoping to find the exact relay to order. After contacting the manufacturer (out of stock on relays currently), I do not want to waste your time or anyone's else and decided to place a special order on the alternative relay suggested by the employee at the local electronics store. On the other hand, I am interested in the voltage divider but I have no experience with that as well. I do not mind learning but I feel terrible as you will have to explain how to work out the relay coil versions, etc. This community is great and I really appreciate your help and others. Thank you.
 

Thread Starter

Jolteon

Joined Feb 6, 2018
24
Have you checked that the pinout dimensions on the data sheet from the link that Ron provided in post#3 ? After looking at the coil resistances of the relays in the data sheet it looked like it could be the 110/120 volt one or the 48 volt one. (With 5K in series with either of them would require about 150 volts. ) It is reasonable to expect this voltage across C2 as it will be somewhere between the RMS and peak value of the input voltage. Working out the dissipation in the series 5K resistor with the 48 volt coil gave a value of about 2 watts. As the two 10 K resistors look to be about 1/2 watt rating it suggests that is more likely to be the 110/120 volt relay.
COULD YOU PLEASE AT LEAST TRY TO MEASURE THE COIL RESISTANCE ON YOU RELAY.

Les
Maybe I am doing it wrong? I set the multimeter at 200 ohms (lowest) and the reading is OL for pins 2-3.
 

LesJones

Joined Jan 8, 2017
4,174
I cant find any pin numbers shown on the data sheet and your pictures of the underside of the relay are so poor I can't read the pin numbers on them. There are only two tracks on the board that are sodered to the relay. These are the coil connections. The 200 ohm range is too low to measure the values of resistance I expect to see. According to the data sheet in the link that Ron provided in post #3 a 48 volt relay coil would have a resistance of 2560 ohms a 110/120 volt relay should be 13445 ohms. I would expect there to be a switch on your meter to select other ranges than 200 ohms. I would also ranges of 2000 ohms (2K) 20000 ohms (20K) 200000 ohms (200K) and probably higher. It may also have an auto range. ) This would initially start with the highest range and step down until it was on the lowest range capable of reading the resistance value you were testing. Select the 20K range. (Or the auto range.)

Les.
 

Reloadron

Joined Jan 15, 2015
7,501
is anyone able to give me a suitable part number or specs for the transformer?
This thread is about 6 months old. What transformer are you talking about? The one shown in post #51? You would do better to start a new thread and post clearly your objective.

Ron

MOD:
Many Thanks, Done that
Eric
 
Last edited by a moderator:

pascal37

Joined Jan 10, 2019
1
Yes, X1 is connected to an auto/on/off switch. At the beginning, I thought this was just a general electronics forum but realized thereafter, it is geared towards electrical engineering which I have no experience with. When I googled "electronic circuit forum", this appeared as the top search and I registered, hoping to find the exact relay to order. After contacting the manufacturer (out of stock on relays currently), I do not want to waste your time or anyone's else and decided to place a special order on the alternative relay suggested by the employee at the local electronics store. On the other hand, I am interested in the voltage divider but I have no experience with that as well. I do not mind learning but I feel terrible as you will have to explain how to work out the relay coil versions, etc. This community is great and I really appreciate your help and others. Thank you.
Hello Jolteon! I have the same trouble as you with my Ivac, I've you find a solution to your faulty relay?
 
Hello Jolteon! I have the same trouble as you with my Ivac, I've you find a solution to your faulty relay?
Has anyone come up with a solution yet? I have the same iVac control with a dead power relay and am attempting to source a replacement. I know this is an old thread but the issue I have is exactly the same.

Thanks
 
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