https://community.element14.com/technologies/motors-and-drives/Motors & Drives discusses the latest trends in motion control and AC or DC motor technology, including FOC, sensorless control, converters, inverters, variable frequency drives, EV powerplants and charging stations.en-USTelligent Community 12https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230592Fri, 12 Sep 2025 02:15:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:7e28667f-61a9-4c87-bca2-e018af7537c9jw0752This circuit is powered with 24VDC from a linear unregulated power supply. It is a pretty beefy supply with a 25Amp bridge and an off board transformer.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230545Tue, 09 Sep 2025 20:02:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:8588f24f-53d4-43be-bfd4-4a11e03cad21DABHi John, She is not painting, but has become active with Zendoodle. I have been doing a lot of timelapse photography with some GoPro camera's I picked up. Got some great Aurora shots last year.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230525Tue, 09 Sep 2025 03:17:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:1e02262e-67d6-4b6f-af3e-753b7d6c12bajw0752I will get this information when the next boards arrive.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230524Tue, 09 Sep 2025 03:16:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:d8a5d9fe-260a-45ae-b348-0d8b9993f79djw0752Thanks - I was very please to see you are still helping people on the forum. Please give our greetings to your wife. Is shee still painting?https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230523Tue, 09 Sep 2025 03:14:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:c68e2273-aa35-41d6-b8d5-ea78e836a1f0jw0752I now have GS2M 2 Amp diodes in stock for future repairs.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230522Tue, 09 Sep 2025 03:11:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a054d2df-788d-41e6-993b-f53119395915jw0752Thanks for your reply, sorry for my absence from this thread. I am a bit over loaded now days. That circuit you posted sure looks close to what I have drawn. I don't have a board right now but three will arrive by weeks end and I will look more closely at the 0.22 resistor and connections to it. I thought it was just a current limiter but it will be best if I make certain.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230481Sun, 07 Sep 2025 14:17:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:e1456f51-6236-49ce-b665-acc9e155d929colporteurI learned something. Now where to put it so I don't forget it.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230480Sun, 07 Sep 2025 02:13:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:9cad5747-89de-407f-9e9f-d987f284ddaddang74I don't have any specific design experience in this area, but a flyback transformer circuit I was looking at did indeed use capacitors in the snubber.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230477Sat, 06 Sep 2025 21:57:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:f556d326-04a1-4e96-af61-20016c06b486robogaryWhat's the power source voltage? Is it from a switched supply or a linear regulated ?https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230476Sat, 06 Sep 2025 21:56:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:4d7d7618-0d3b-4b3a-a714-cfd135e028e7robogaryThink some small snubber cap could help if there is excessive rate of rise on the switch?https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230475Sat, 06 Sep 2025 21:13:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:62df722f-de2f-4296-9a9f-41b3baae40b6dang74I am with you on the diodes being the weakest link. I was tempted to suggest ditching the diodes altogether, but Doug later mentions that they act as snubbers and absorb spikes... so maybe using diodes with a higher rated current as he suggests is the best way.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230473Sat, 06 Sep 2025 20:27:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:ecb9b487-ed2d-4f5d-a49d-7beff67b921eDABHi John, I am glad you are back. I hope you are doing well.https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230440Thu, 04 Sep 2025 10:50:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:7ddc7cf7-823b-4a90-9cab-f3d5ca75e6ecmichaelkellettLTSpice file here: https://www.dropbox.com/scl/fo/876wu0j1vuus2e9t4yz0k/ABlNGiq6fHZOnWuOwdkZHkI?rlkey=9rs366j5r73tu3lft7f4a8rgg&dl=0 MKhttps://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230439Thu, 04 Sep 2025 10:49:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:36b633d5-fe9a-4a43-a39c-98fdec7a9e28jc2048Hello John, I would think that the designer was familiar with this converter topology https://www.vishay.com/docs/91616/twoswitch.pdf In the case of the forward converter with a transformer, it guarantees the magnetic reset of the core (with PWM less than 50%), stopping it stepping to saturation, and has a small benefit in recycling much of the magnetizing and leakage energy back to the supply (and thereby lowering the dissipation in the 'snubber' components). I suppose those might also be of benefit with PWM-ing a solenoid, but it's not an area I'm familiar with. Are you sure there is no other connection to the top of what looks like it has to be a current-sense resistor (the 0.22R)?https://community.element14.com/technologies/motors-and-drives/f/forum/56128/driver-circuit-for-a-reciprocating-water-pump-in-a-medical-device/230438Thu, 04 Sep 2025 10:26:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:c44a047a-700e-4c34-9111-51c17cabf8d2jw0752I will look into the possibility of upsizing the snubber diodes. thanks