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OCServo

OCServo OCS-521HV Servo Motor

  • Peak stall torque (kg·cm): 6V: 41; 7.4V: 48; 8.4V: 55
  • Operating Voltage: 6.0V / 7.4V / 8.4V
  • No load speed (sec/60°): 6V: 0.158; 7.4V: 0.132; 8.4V: 0.108
  • Motor Type: Coreless motor
  • Gear Type: Stainless Steel
$80
Version

Warranty
  • 1-year limited warranty for the main unit.
  • 6-month limited warranty for the battery.
  • For service support, please contact customer care with proof of purchase.

Shipping

• Free shipping on qualifying orders. Eligibility and exact rates are calculated at checkout.
• Typical delivery 9 – 15 business days.
• Need it faster or shipping something large? Contact us for expedited options and a freight quote.

Developer Support

OCServo OCS-521HV dimensional drawing.pdf ▶ OCServo OCS-521HV technical specifications.pdf ▶
OCServo OCS-521HV Servo Motor detail image
OCServo OCS-521HV Servo Motor detail image
▤ PARAMETER ⌃
Product Name
8.4V52kg-cm High Voltage Digital Servo
Item No.
OCS-521HV
Storage Temperature Range
-20°C ~ 70°C
Operating Temperature Range
-15°C ~ 65°C
Test Temperature
25°C ± 5°C
Test Humidity
65% ± 10%
Size (mm)
20 × 40 × 41
Weight (g)
51 (excluding accessory)
Gear Type
Stainless Steel
Limit Angle
210°
Bearings
2 Ball bearings
Output Spline
25T - Φ5.94mm
Horn Type
Plastic POM
Case Material
Aluminum CNC
Connector Wire
300 mm
Motor Type
Coreless motor
Waterproof Performance
Yes
Operating Voltage
6.0V / 7.4V / 8.4V
No load speed (sec/60°)
6V: 0.158; 7.4V: 0.132; 8.4V: 0.108
Running current (at no load) (mA)
6V: 350; 7.4V: 390; 8.4V: 450
Peak stall torque (kg·cm)
6V: 41; 7.4V: 48; 8.4V: 55
Stall current (A)
6V: 4.4; 7.4V: 5.4; 8.4V: 6.2
Command Signal
PWM 50~333Hz
Amplifier Type
Digital Controller
Pulse Width Range
800~2200 μsec
Neutral Position
1500 μsec
Running Degree
96° (when 1000~2000 μsec)
Dead Band Width
1 μsec
Rotating Direction
CCW (when 1000~2000 μsec)

Frequently Asked Questions

Where do you ship from?

Robotopian operates fulfillment capabilities in Shenzhen, China and Santa Clara, California. Depending on the product, inventory condition, production arrangement, and destination, orders may ship from different locations.

At this time, most newly manufactured robot orders ship primarily from Shenzhen, China. Selected inventory may also ship from Santa Clara when available.

Why are many orders shipped from China?

Most robotic products today still rely heavily on China-based supply chains. Many models enter sourcing, production scheduling, or manufacturing only after an order is placed.

By working directly with the China supply chain and our Shenzhen fulfillment system, Robotopian can coordinate procurement, warehouse handling, international transportation, and cross-border delivery more efficiently. In many cases, this also helps us provide a clearer cost structure and a more competitive fulfillment model.

In other words, shipping directly from China does not necessarily make the process more complicated. In many cases, it is actually a more direct and efficient way to fulfill specialized robotics orders.

Which countries do you ship to?

Robotopian ships to a broad range of major countries and regions worldwide. Actual destination availability may vary depending on the product type, local import regulations, shipping conditions, and fulfillment feasibility.

Common destinations may include, but are not limited to:

United States

Canada

United Kingdom

Germany

France

Netherlands

Australia

New Zealand

Singapore

Japan

If your country or region is not shown at checkout, please contact the Robotopian team and we will evaluate a suitable shipping option for you.

Does your pricing include duties, taxes, and shipping costs?

Where applicable, Robotopian aims to include standard cross-border fulfillment costs in the quoted order total and to make the major cost components clear before checkout.

This may include:
product price
international shipping
standard customs clearance handling
applicable import duties and taxes
last-mile delivery
standard residential or remote-area surcharges
applicable special transportation surcharges

Why was my order split into multiple packages?

In some cases, one order may be split into multiple parcels or shipped from different fulfillment locations.

This may happen because:
the main unit and accessories become ready at different times
different items are fulfilled from different warehouses
some items are ready earlier and can ship first
different products require different shipping arrangements

If split shipment occurs, Robotopian will make reasonable efforts to share the relevant shipping information.

Do I need to handle customs clearance myself?

In most cases, no.

For standard cross-border orders, Robotopian will usually coordinate shipping, customs, and delivery arrangements to reduce complexity for the customer.

In some cases, local customs authorities, delivery agents, or carriers may contact the recipient directly to verify delivery information, recipient identity, or local clearance requirements. If that happens, you may contact the Robotopian team and we will assist.

What should I do if I am asked to pay an extra charge?

If you are asked to pay a charge that you believe should already have been included in your quoted order total, please contact the Robotopian team promptly.

We will review the quotation, payment record, shipping arrangement, and actual situation. If the charge is confirmed to fall within the covered standard scope, Robotopian will assist in resolving the issue.

What should I do if my package is lost, damaged, or shows a delivery exception?

If your order experiences any of the following:

lost package
obvious package damage
delivery exception
delivery status inconsistent with the actual receipt of goods

please contact the Robotopian team within 72 hours. We will assist, based on the actual case, in following up with the carrier, customs intermediary, or related service providers.

Do you offer additional shipping insurance or shipment protection?

For certain eligible orders, Robotopian may be able to provide additional shipping protection or commercial insurance options upon request.

Because eligibility depends on the product, destination, and shipping method, availability, structure, and pricing will need to be confirmed case by case.

Do you offer appointment delivery, installation, or special delivery services?

For certain eligible orders, Robotopian may offer additional services such as:

appointment-based delivery
special delivery arrangements
on-site installation
deployment support
other project-based customized fulfillment services

These services are generally not included in standard delivery. If needed, please contact the Robotopian team in advance to confirm feasibility and pricing.

Is the order considered delivered once it is signed for?

Generally, yes. Once a shipment has been signed for, it is usually considered delivered.

If you discover a delivery issue, missing goods, or another shipping-related problem after receipt, please contact the Robotopian team within 72 hours so we can assist promptly.

How long will it take before my order ships?

That depends on the type of product you ordered.

In-stock items: usually move into warehouse processing and dispatch shortly after payment is confirmed.

Pre-order items: dispatch timing depends on the brand’s supply schedule and incoming availability.

Made-to-order / production-scheduled items: these typically go through sourcing, production, or scheduling first. From confirmed payment to the point when the order is ready for dispatch from Shenzhen, the estimated lead time is usually 10–30 days.

For U.S. orders that have completed preparation and shipped from Shenzhen, the estimated transit time is typically 3–7 business days. Delivery timing for other destinations will vary.

Why hasn’t my tracking updated right after shipment?

This is common in international shipping.

After an order is packed and assigned for shipment, tracking may not update immediately until the parcel is scanned by the first carrier, handed through the airport process, or entered into the destination country’s local carrier network.

If your tracking does not change during the first few days after shipment, that is usually normal and does not necessarily mean the parcel is not moving.

Will I receive a tracking number after shipment?

Yes. Once the order is officially dispatched from Shenzhen or the applicable fulfillment location, Robotopian will provide a tracking number so you can follow the shipment progress.

Depending on the shipping route, some orders may show limited tracking information during the early stages of international transit. Tracking details usually become more complete as the shipment moves through later carrier networks.

Can I cancel my order?

Yes, but the rules depend on the order stage.

Orders may be cancelled free of charge within 24 hours of placement.

If the order has already entered sourcing, production, scheduling, or manufacturing, Robotopian will refund 60% of the amount paid and retain 40% as a cancellation fee. This helps cover supplier deposits, scheduling allocation, and related processing costs.

Whether the order has entered one of these stages will be determined based on Robotopian’s internal system records and supply chain confirmation.

Can I change my shipping address?

Yes, but please contact us as early as possible.

You may request an address change before the order is officially dispatched. If the order has already shipped, additional charges caused by rerouting, address changes, or shipment interception may apply and will generally be the customer’s responsibility.

What happens if I refuse delivery?

If an order has already shipped and the customer refuses delivery, the parcel will usually be returned. Any return shipping charges, return handling fees, and other incurred costs will generally be the responsibility of the customer.

If you have concerns about the order, it is best to contact the Robotopian team before the shipment is dispatched.

  • Or send us a message

    hi@robotopian.com