Want to learn how to power/control a fan (ebm-papst RV45) - Page 1
Forum section: electronics / beginners

author: engineheat
author_rank: Frequent Contributor
timestamp: June 29, 2024, 11:19:57 pm
content: HiI want to be able to use this fan for a project and be able to control its speed:https://www.mouser.com/new/ebm-papst/ebm-papst-rv45-centrifugal-fans/It has some datasheet:https://www.mouser.com/pdfDocs/RV45DriveElectronicsDatasheet.pdfBut I'm not able to understand it.I want to power it using 12V, and it states and voltage range of 7-30V, so I think I'm good. But starting on page 4 of the datasheet, they have so many different voltage values it's hard to make sense of it.It also seems to require their own controller (page 2 of datasheet). Will I be able to control the speed using Arduino (PWM)?I don't see them explaining what Ubs, Ra, or Us mean.I hope to be able to understand this fan.Thanks

author: JustMeHere
author_rank: Frequent Contributor
timestamp: June 30, 2024, 12:00:15 am
content: The voltage range is 16v to 30v with 24v being preferred.You control the speed with a 0v-12v signal. See section 2.1 of you datasheet.

author: engineheat
author_rank: Frequent Contributor
timestamp: June 30, 2024, 10:27:37 pm
content: So that controller with 4 wires is mandatory?The control voltage (0-12V) goes to wire 3 (Control) and the voltage is linearly related to the speed?Wire 4 is for tachometer which should be optional correct?And wire 1 is the voltage to the fan (16 - 30 V), correct?Thanks

author: JustMeHere
author_rank: Frequent Contributor
timestamp: July 01, 2024, 04:30:01 pm
content: QuoteNo. Power can come straight from 24v source.The controller only needs to share the ground, and one signal. I'd try a digital pot or a DAC.QuoteYes, but not linear. See the datasheet.QuoteYes, it looks optional.QuoteYes

author: engineheat
author_rank: Frequent Contributor
timestamp: August 10, 2024, 03:24:58 am
content: Quote from: JustMeHere on June 30, 2024, 12:00:15 amHi again,I have some 18V batteries so I think I will try to use that to power the fan. I don't need anywhere close to full power anyway.Aside from powering the blower, can I use the same 18V battery to control the speed by using voltage division and a potentiometer to get a variable voltage of 0v-12v at the control? I think the current draw will be minimal if I use high resistance resistors and this seems the easiest way for me.To get the tachometer to work (I've provided relevant images below), it seems I need to supply a voltage (tacho operating voltage) at wire 4 (U_bs) with a voltage <= 30V. Then, I can count the number of pulses at U_s (tacho signal).I should be able to use the same 18V battery for U_bs, since it's <= 30V.U_s has a high and a low. The high seems fixed at 30V regardless of U_bs. The low is determined by resistor R_a, which is what I provide. I need to ensure that the sink current is <=20mA with a suitable value for R_a using the equation they provided.The datasheet also provides the following schematics with the 10k and 15k resistors. But I think those are internal to the drive electronics and is not something I need to worry about.Please let me know if I understood it correctly. Appreciate it.Thanks