Telus doesn't offer unlimited data plans where it's always high speed data. There are certain clearly advertised limits and after you hit them, the speed is throttled.
From Telus Mobility's plans FAQ:
Q. Does TELUS offer unlimited/endless data plans?
A. While our Peace of Mind plans allow you to use unlimited data, your speeds will
be slowed once you reach the plans GB allowance. For example, if a plan offers 20GB of high‑speed data, once you pass 20GB, you’ll
notice slower speeds. However, you will still be able to use your endless data
without worrying about data limits or overages.
Peace of Mind Plans allow you to use as much data as you like while in Canada and
never be charged data overages. After your plan’s high-speed threshold, TELUS will
reduce the maximum speed for the remainder of your billing cycle to a maximum of
512 Kbps. This means you’ll still be able to browse the Internet and use email but
video quality will be reduced and other high-bandwidth applications will take longer
to load. Please refer to TELUS’ Fair Use Policy at telus.com/fairusepolicy for
Which plan are you actually on?
How much data have you used so far this month?
High demand data will of course be throttled more then surfing the web. The fact you already passed your allotted limit for the month. Don’t expect more allotted min speeds for high consumption sites.
3/4 bars doesn’t mean much you can have slow speeds even with 4 “bars” a variety of factors exist for data speeds.
What speeds are you thinking you’ll achieve?You clearly stated you hit your monthly limit, and it’s now operating at a reduced throughput. Telus clearly will throttle your speeds according to the traffic. What normal download rates vs capped are two different things regardless of signal strength.
The number of bars on your phone does not equal the speed of the connection in mbps. 4 bars reflects the signal strength between your phone and the tower, not the specific speed of the connection. In a few rare places in the BC interior I've had 4 bars and over 300mbps on LTE. In Vancouver I've had over 100mbps with 4 bars. Just depends on where you are and the speed the tower is capable of.
Additionally, 512kbps (kilobits) is approximately 60Kb/s (kilobytes).
No, 512kbps isn't equal to half a megabyte. Half a megabit yes but that's still 60kB/s. There are 8 bits in every byte. 512kbps / 8 bits = 64kB.
If you're still able to download a 200mb file in 40 minutes, that's fast. In theory at 512kbps that file should take closer to 54 minutes to download. The calculation of 6 minutes you have is if you're assuming the connection is 512kB/s or 4mbps which is far faster than what you've got.