From a6e14085046c7cf24f8ed27673a9c365d1565bf1 Mon Sep 17 00:00:00 2001
From: jaseg <git@jaseg.de>
Date: Tue, 13 Jul 2021 15:58:30 +0200
Subject: Give source on motor power estimate

compare to large sunon fan
---
 paper/ihsm_paper.tex | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

(limited to 'paper/ihsm_paper.tex')

diff --git a/paper/ihsm_paper.tex b/paper/ihsm_paper.tex
index 851da46..f4cea28 100644
--- a/paper/ihsm_paper.tex
+++ b/paper/ihsm_paper.tex
@@ -420,9 +420,13 @@ motor requires more power than the mesh monitoring circuit of a traditional HSM.
 Uninterruptible Power Supply (UPS) can be used, but in practice a productized IHSM might have a smaller backup battery
 integrated into its case. Conservatively assuming an average operating power consumption of $\SI{10}{\watt}$ for an
 IHSM's motor, a single large laptop battery with a capacity of $\SI{100}{\watt\hour}$~\cite{faa2018} could already power
-an IHSM for 10 hours continuously. If a built-in battery is undesirable, or if power outages of more than a few seconds
-at a time are unlikely (e.g.\ because the IHSM is connected to an external UPS or generator), the IHSM's rotor itself
-can be used as a flywheel for energy storage.
+an IHSM for 10 hours continuously. $\SI{10}{\watt}$ is a reasonable high estimate given that there are large industrial
+fans rated at lower wattages. For example, \texttt{CF2207LBL-000U-HB9}, a $\SI{250}{\milli\meter}$ diameter
+$\SI{7.8}{\meter^3\per\minute}$ industrial axial fan made by Sunon is rated at only
+$\SI{6.6}{\watt}$\footnote{\url{https://www.digikey.com/en/products/detail/sunon-fans/CF2207LBL-000U-HB9/9083282}}.  If
+a built-in battery is undesirable, or if power outages of more than a few seconds at a time are unlikely (e.g.\ because
+the IHSM is connected to an external UPS or generator), the IHSM's rotor itself can be used as a flywheel for energy
+storage.
 
 \paragraph{Spurious alarms.}
 Even with all components working to their specification, an IHSM could still catastrophically fail if for some reason
-- 
cgit 

